Water Quality Information
Center of
the National Agricultural Library
Agricultural Research Service, U.S. Department of Agriculture
Simulation Models, GIS and Nonpoint-Source Pollution (I)
January 1991 - December 1993
Quick Bibliography Series: QB 94-06 (Updates QB 92-69)
337 citations from AGRICOLA
Joe Makuch and Bonnie Emmert
Water Quality Information Center
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Simulation Models, GIS and Nonpoint-Source Pollution
1 NAL Call. No.: 56.8 SO3
An accurate and numerically stable model for one-dimensional
solute transport in soils.
Moldrup, P.; Yamaguchi, T.; Hansen, J.A.; Rolston, D.E.
Baltimore, Md. : Williams & Wilkins; 1992 Apr.
Soil science v. 153 (4): p. 261-273; 1992 Apr. Includes
references.
Language: English
Descriptors: Soil solution; Solutes; Transport processes;
Simulation models; Mathematical models; Soil water movement;
Convection; Dispersion; Comparisons; Accuracy; Soil testing;
Soil water content; Loam soils
2 NAL Call. No.: QH540.N3
Adsorption-desorption methodologies and selected estimation
techniques for transport-modeling parameters.
Roy, W.R.
Berlin, W. Ger. : Springer-Verlag; 1993.
NATO ASI series : Series G : Ecological sciences v. 32: p.
169-188; 1993. In the series analytic: Migration and fate of
pollutants in soils and subsoils / edited by D. Petruzzelli
and F.G. Helfferich. Proceedings of the NATO Advanced Study
Institute, May 24-June 5, 1992, Maratea, Italy. Includes
references.
Language: English
Descriptors: Soil pollution; Pollutants; Adsorption;
Desorption; Transport processes; Computer simulation; Vapor;
Organic compounds; Volatilization; Groundwater pollution;
Trichloroethylene; Microbial degradation
3 NAL Call. No.: HD1773.A2N6
Aggregate analysis of site-specific pollution problems: the
case of groundwater contamination from agriculture.
Opaluch, J.J.; Segerson, K.
Morgantown, W.Va. : The Northeastern Agricultural and Resource
Economics Association; 1991 Apr.
Northeastern journal of agricultural and resource economics v.
20 (1): p. 83-97; 1991 Apr. Paper submitted in response to
call for papers on the theme "The Effects of Agricultural
Production on Environmental Quality.". Includes references.
Language: English
Descriptors: Groundwater; Contamination; Water pollution;
Agricultural sector; Agricultural policy; Microeconomic
analysis; Aggregate data; Site factors; Spatial distribution;
Information systems; Mathematical models
4 NAL Call. No.: S900.R39
Analysing water quality policy using microeconomic models of
production practices and biophysical flow models of
environmental processes. Weaver, R.D.; Harper, J.K.
London : Harwood Academic Publishers; 1993.
Resource management and optimization v. 9 (2): p. 95-105;
1993. Includes references.
Language: English
Descriptors: U.S.A.; Water quality; Water policy;
Microeconomics; Technology; Environmental factors;
Mathematical models
5 NAL Call. No.: 292.8 W295
An analytical solution for one-dimensional transport in porous
media with an exponential dispersion function.
Yates, S.R.
Washington, D.C. : American Geophysical Union; 1992 Aug.
Water resources research v. 28 (8): p. 2149-2154; 1992 Aug.
Includes references.
Language: English
Descriptors: Transport processes; Solutes; Hydrodynamic
dispersion; Subsurface layers; Equations; Mathematical models
Abstract: An analytical solution describing the transport of
dissolved substances in heterogeneous porous media with an
asymptotic distance-dependent dispersion relationship has been
developed. The solution has a dispersion function which is
linear near the origin (i.e., for short travel distances) and
approaches an asymptotic value as the travel distance becomes
infinite. This solution can be used to characterize
differences in the transport process relative to both the
classical convection-dispersion equation which assumes that
the hydrodynamic dispersion in the porous medium remains
constant and a dispersion solution which has a strictly linear
dispersion function. The form of the hydrodynamic dispersion
function used in the analytical solution is D(x) = alpha(x)
average pore water velocity + D(diff), where a(x) = a L[1 -e(-
bx/L)]. The proposed model may provide an alternate means for
obtaining a description of the transport of solutes in
heterogeneous porous media, when the scale dependence of the
dispersion relationship follows the behavior given by
alpha(x). The overall behavior of the model is illustrated by
several examples for constant concentration and flux boundary
conditions.
6 NAL Call. No.: 56.9 SO3
Analytical solution of solute diffusion and biodegradation in
spherical aggregates.
Priesack, E.
Madison, Wis. : The Society; 1991 Sep.
Soil Science Society of America journal v. 55 (5): p.
1227-1230; 1991 Sep. Includes references.
Language: English
Descriptors: Microbial degradation; Soil flora; Organic
compounds; Solutes; Diffusion; Soil solution; Aggregates;
Spatial distribution; Mathematical models; Soil pore system;
Pores; Transport processes; Movement in soil; Diffusivity;
Growth rate; Adsorption; Biomass; Substrates
Abstract: Microbial degradation and transformation of
substances in soils plays a crucial role ii the nutrient
turnover of ecosystems. To quantify these processes, a
mathematical description is needed. For this purpose, an
analytical solution to a model of solute diffusion and
biodegradation in soil aggregates was developed. The model is
a first approach toward understanding the influence of
geometric arrangement of microorganisms and substrates in
structured soils. These soils are considered to consist of
uniformly sized and shaped aggregates surrounded by surface
films of the soil solution. The model simulates transient
diffusion of finite substrate amounts from the surface films
into spherical aggregates. Biodegradation is considered for
the special case of unlimited microbial growth, and adsorption
is assumed to follow a linear Freundlich isotherm. The system
is represented by a composite sphere, the outer sphere being
the solution film and the inner sphere representing the soil
aggregate. The diffusion equations are solved by Laplace
transformation. The model solution gives a direct relationship
between the initial substrate and biomass concentrations, the
diffusion coefficient, the specific growth rate, and the
adsorption coefficient. Good agreement between this closed
form solution and numerical solutions is obtained for
diffusion with and without biodegradation. Since the substrate
is exhausted by organisms close to the surface, the centers of
large aggregates are not reached by the diffusing substrate.
These unaffected centers become lager as the growth rate is
higher, the diffusion constant is lower, and adsorption of the
substrate is stronger.
7 NAL Call. No.: 292.8 W295
Analytical solutions for solute transport in three-dimensional
semi-infinite porous media.
Leij, F.J.; Skaggs, T.H.; Van Genuchten, M.T.
Washington, D.C. : American Geophysical Union; 1991 Oct.
Water resources research v. 27 (10): p. 2719-2733; 1991 Oct.
Includes references.
Language: English
Descriptors: Transport processes; Solutes; Flow; Mathematical
models; Prediction
Abstract: This paper presents several analytical solutions
for three-dimensional solute transport in semi-infinite porous
media with unidirectional flow using first-type (or
concentration) and third-type (or flux) boundary conditions at
the inlet location of the medium. The solutions may be used
for predicting solute concentrations in homogeneous media,
verification of more comprehensive numerical models, and
laboratory or field determination of solute transport
parameters. The transport equation incorporates terms
accounting for advection, dispersion, zero-order production,
and first-order decay. General solutions were derived for an
arbitrary initial distribution and solute input with the help
of Laplace, Fourier, and Hankel transforms. Specific solutions
are presented for rectangular and circular solute inflow
regions, as well as for solutes initially present in the form
of parallelepipedal or cylindrical regions of the medium. The
solutions were mathematically verified against simplified
analytical solutions. Examples of concentration profiles are
presented for several solute transport parameters using both
first- and third-type boundary conditions. A mass balance
constraint is defined based on a prescribed solute influx; the
third-type condition is shown to conserve mass whereas the
first-type condition was found to always overestimate resident
solute concentrations in the medium.
8 NAL Call. No.: 292.8 W295
Applicability of the steady state flow assumption for solute
advection in field soils.
Destouni, G.
Washington, D.C. : American Geophysical Union; 1991 Aug.
Water resources research v. 27 (8): p. 2129-2140; 1991 Aug.
Includes references.
Language: English
Descriptors: Agricultural soils; Solutes; Transport processes;
Transient flow; Soil water movement; Soil texture; Soil depth;
Plant water relations; Simulation models
Abstract: A comparison between solute travel times predicted
by a transient and a steady state flow model is made. Data for
five different soil profiles with detailed measurements of
their hydraulic properties and their variation with depth are
used. Daily measurements of meteorological data are used as
input parameters in the transient simulations that include
snow and frost dynamics, interception of precipitation, and
evapotranspiration. The parameters of the steady state flow
model are related to the measured soil properties and the
hydrological characteristics of each transient simulation.
Furthermore, the influence of solute injection time on the
predicted travel time is analyzed, and the effect of root
water uptake on the applicability, of the steady state flow
assumption for solute advection is investigated. The results
indicate that the steady, state flow model may provide
estimates of the mean solute advection that are compatible
with those of the transient flow model. The constant rate of
recharge in the steady state flow, model should then be
interpreted as the average annual effective infiltration
(i.e., infiltration minus actual evapotranspiration). When
root water uptake is accounted for, an arithmetic depth-
averaging of the soil parameters appears to yield steady state
estimates of arrival time that are closest to the transient
predictions. When root water uptake is neglected, a harmonic
depth-averaging of the soil parameters provides the best
steady state results. The discrepancy between the arrival
times predicted with the two flow models decreases with the
travel distance from the soil surface.
9 NAL Call. No.: 100 G29So no.372
Application and enhancement of hydrologic/water quality
models.. S-211 final report
Thomas, Daniel L.; Shirmohammadi, Adel,_1952-; Engel, Bernard
A. Tifton, Ga. : Biological and Agricultural Engineering Dept.
: University of Georgia-Coastal Plain Experiment Station,;
1992.
xi, 114 p. : ill. ; 28 cm. (Southern cooperative series
bulletin ; no. 372). Running title: S-211 final report. June,
1992. Includes bibliographical references.
Language: English; English
Descriptors: Hydrology; Water quality
10 NAL Call. No.: SB951.P47
Application and validation of pesticide leaching models.
Klein, M.
Essex : Elsevier Applied Science Publishers; 1991.
Pesticide science v. 31 (3): p. 389-398; 1991. Includes
references.
Language: English
Descriptors: German federal republic; Bentazone; Cloethocarb;
Simulation models; Environmental factors; Leaching;
Lysimeters; Pesticide residues; Soil properties; Climatic
factors
Abstract: Two lysimeter studies with the pesticides
cloethocarb and bentazone were used to validate a modified
version of the computer model SESOIL (Seasonal Soil
Compartment Model), developed by Bonazountas and Wagner and to
transfer the results of the lysimeter study to another climate
scenario. For cloethocarb, an experimental insecticide without
marked mobility in the soil, as indicated by the lysimeter
study, the simulations were in excellent agreement with the
lysimeter study. Calculations for bentazone revealed higher
leaching than found in the lysimeter study. This discrepancy
was resolved by a more careful and realistic inclusion of
sorption in the lysimeter soil into the simulation model.
11 NAL Call. No.: 292.8 J82
An application of a physically based semi-distributed model to
the Balquhidder catchments.
Robson, A.J.; Whitehead, P.G.; Johnson, R.C.
Amsterdam : Elsevier Scientific Publishers, B.V.; 1993 May15.
Journal of hydrology v. 145 (3/4): p. 357-370; 1993 May15.
Special Issue: The Balquhidder Catchment and Process Studies /
edited by P.G. Whitehead and I.R. Calder. Includes
references.
Language: English
Descriptors: Scotland; Watersheds; Simulation models;
Catchment hydrology; Rain; Runoff; Flow
Abstract: A physically based semi-distributed model,
TOPMODEL, is applied to the two catchments at Balquhidder. The
model uses a topographic index which highlights hydrologically
significant areas within the catchments. The model is used to
simulate runoff and to compare the behaviour of the two
catchments. The results indicate that a large proportion of
stream water is generated from saturated contributing areas
(source areas); the Monachyle has higher contributions of
water of this type. The results may also indicate that the
hydrology of the Monachyle catchment has changed following
agricultural improvement by increased drainage; a damped
subsurface response is observed.
12 NAL Call. No.: QA76.76.E95A5
Application of case-based reasoning concepts to the WEPP soil
erosion model. Meyer, C.R.; Flanagan, D.C.
Moscow, Idaho : AI Applications; 1992.
AI applications v. 6 (3): p. 63-71; 1992. Includes
references.
Language: English
Descriptors: U.S.A.; Water erosion; Prediction; Simulation
models; Information retrieval; Usda; Improvement; Management;
Practice; Information storage; Data banks; Program
development; Computer techniques
13 NAL Call. No.: 56.9 SO3
Applications of a laser scanner to quantify soil
microtopography. Huang, C.H.; Bradford, J.M.
Madison, Wis. : The Society; 1992 Jan.
Soil Science Society of America journal v. 56 (1): p. 14-21;
1992 Jan. Includes references.
Language: English
Descriptors: North Carolina; Hapludults; Inceptisols; Surface
roughness; Measurement; Quantitative techniques; Surface
layers; Topography; Height; Spatial variation; Mathematical
models; Mathematics; Transport processes; Soil boundaries;
Artificial precipitation; Tillage; Interrill erosion; Soil
water content; Size; Lasers
Abstract: Many transport processes on or across the soil
surface boundary are controlled by surface microtopography, or
roughness. How roughness affects the transport process depends
on the length scale of the process. The most commonly used
method of expressing soil surface roughness, the roughness
length or random roughness, is constrained by the measurement
technique and does not embody the concept of scale. The
structural function, or variogram, plotted on a log-log scale
was used in this study to express the surface roughness at
different scales. With the aid of a laser scanner, surface
topography was measured down to 0.5-mm grid spacing. Data
collected from a variety of surface conditions showed that
soil roughness can be quantified by a combination of fractal
and Markov-Gaussian processes at different scales. Potential
applications of the roughness quantification were also
discussed.
14 NAL Call. No.: TD426.J68
An approach to estimating uncertainties in modeling transport
of solutes through soils.
Zhang, H.; Haan, C.T.; Nofziger, D.L.
Amsterdam : Elsevier; 1993 Feb.
Journal of contaminant hydrology v. 12 (1/2): p. 35-50; 1993
Feb. Includes references.
Language: English
Descriptors: Soil pollution; Groundwater pollution;
Pollutants; Chemicals; Solutes; Movement in soil; Uncertainty;
Rain; Variation; Prediction; Simulation models
15 NAL Call. No.: 292.8 W295
Approximate analytical solution for soil chemical transfer to
runoff: a modified boundary condition.
Wallach, R.
Washington, D.C. : American Geophysical Union; 1993 May.
Water resources research v. 29 (5): p. 1467-1474; 1993 May.
Includes references.
Language: English
Descriptors: Agricultural chemicals; Soil solution; Surface
water; Runoff water; Overland flow; Boundaries; Transport
processes; Equations; Mathematical models; Comparisons
Abstract: Two mass balance equations were used to model the
transfer of dissolved chemicals from the soil solution to the
surface runoff water and the transport of these chemicals to
the field outlet. One mass balance equation was written for
chemicals dissolved in the overland water, the other for
chemicals within the soil profile. Chemical input into the
surface water (upper boundary condition) was expressed as a
rate-limited convective mass transfer, depending on both soil
surface and runoff concentrations. Isolating a slow and fast
time scale and scaling the mass balance equations to the slow
one yielded a parameter, epsilon, which multiplies the time
derivative of the mass balance equation written for overland
flow. In most cases epsilon << 1, providing a singular
perturbation problem that was solved by using the method of
matched asymptotic expansion. The approximate solution,
uniformly valid over the entire domain, was made up of two
terms: a leading-order solution and a first-order solution,
the latter of which was relatively small, even for epsilon =
O(1). The leading-order solution was compared with that for a
simpler case, in which the convective mass transfer (upper
boundary condition) depends only on the soil surface
concentration. The comparison indicated those limited cases to
which the simpler boundary condition can be applied resulting
in a very small error. Although it is not possible to get a
strictly analytical solution for a problem involving a
modified upper boundary condition, the approximate analytical
solution is easily obtained.
16 NAL Call. No.: 292.9 AM34
Assessing ground water pollution potential from nitrogen
fertilizer using a geographic information system.
Halliday, S.L.; Wolfe, M.L.
Bethesda, Md. : American Water Resources Association; 1991
Mar. Water resources bulletin v. 27 (2): p. 237-245; 1991 Mar.
Includes references.
Language: English
Descriptors: Texas; Groundwater pollution; Nitrogen
fertilizers; Pollutants; Susceptibility; Expert systems
Abstract: A geographic information system (GRASS 3.1) was
used to correlate the availability of nitrogen fertilizer with
the susceptibility of ground water to pollution in Texas to
identify potential ground water quality problems. An
agricultural pollution susceptibility map, produced by the
Texas Water Commission using the DRASTIC methodology, was
combined with information on cropped areas, recommended
nitrogen fertilizer application rates, and aquifer outcrops. A
Nitrogen Fertilizer Pollution Potential Index was generated,
identifying 24 percent or Texas within the high pollution
potential category. An analysis of the susceptibility of major
aquifer outcrops to potential pollution from nitrogen
fertilizer indicated that 34 percent of the outcrop areas fall
in the high pollution potential range. It is proposed that
correlating the availability of a pollutant with an assessment
of the susceptibility of ground water to pollution yields a
more accurate screening tool for identifying potential
pollution problems than considering susceptibility alone.
17 NAL Call. No.: S542.A8A34
Assessment and alleviation of the impact of runoff and erosion
on crop production.
Okwach, G.E.; Williams, J.; Wambua, J.
Canberra : Australian Centre for International Agricultural
Research; 1992. ACIAR proceedings (41): p. 72-82; 1992. In
the series analytic: A search for strategies for sustainable
dryland cropping in semi-arid eastern Kenya / edited by M.E.
Probert. Paper presented at a symposium held Dec 10-11, 1990,
Nairobi, Kenya. Includes references.
Language: English
Descriptors: Kenya; Runoff; Erosion; Soil fertility; Tillage;
Mulches; Soil conservation; Semiarid zones; Simulation models
18 NAL Call. No.: 292.8 J82
An assessment of the dynamic response characteristics of
streamflow in the Balquhidder catchments.
Jakeman, A.J.; Littlewood, I.G.; Whitehead, P.G.
Amsterdam : Elsevier Scientific Publishers, B.V.; 1993 May15.
Journal of hydrology v. 145 (3/4): p. 337-355; 1993 May15.
Special Issue: The Balquhidder Catchment and Process Studies /
edited by P.G. Whitehead and I.R. Calder. Includes
references.
Language: English
Descriptors: Scotland; Watersheds; Stream flow; Catchment
hydrology; Clearcutting; Afforestation; Rain; Runoff;
Simulation models
Abstract: The method of rainfall-runoff modelling and
hydrograph separation developed in an earlier paper is applied
to the Kirkton and Monachyle catchments situated near
Balquhidder, Scotland. Using daily rainfall and streamflow
data, natural differences between the quick and slow flow
responses for the Kirkton and Monachyle catchments are
quantified, and an attempt is made to detect the impact of
land-use changes on these natural regimes (clear-felling in
part of the Kirkton and drainage ditching and conifer planting
in part of the Monachyle). Dynamic response characteristics
for the quick and slow flow components are defined in terms of
time constants, relative throughput volumes and unit
hydrograph peaks. These response characteristics are estimated
and compared for annual periods before and after the land-use
changes. For both the Kirkton and Monachyle, the effects of
the land-use changes (affecting part of each catchment) on the
hydrological response are not detectable at the catchment
outlets. The interannual variation of the dynamic response
characteristics falls within the inherent uncertainty expected
if no land-use changes had occurred.
19 NAL Call. No.: aS21.A8U5/ARS
Basin scale water quality model.
Arnold, J.G.
Washington, D.C. : The Service; 1993.
Reprints - U.S. Department of Agriculture, Agricultural
Research Service [512]: 9 p.; 1993. Indexed from reprint:
Proceedings of the CREAMS and GLEAMS Conference. p. 192-200.
Includes references.
Language: English
Descriptors: Catchment hydrology; Simulation models; Water
quality; Climatic factors; Geological sedimentation; Runoff;
Agricultural chemicals
20 NAL Call. No.: S612.I756
Best management of pesticide--furrow irrigation systems.
Ranjha, A.Y.; Peralta, R.C.; Requena, A.M.; Deer, H.M.;
Ehteshami, M.; Hill, R.W.; Walker, W.R.
Berlin, W. Ger. : Springer International; 1992.
Irrigation science v. 13 (1): p. 9-14; 1992. Includes
references.
Language: English
Descriptors: Utah; Furrow irrigation; Design; Simulation
models; Pesticides; Leaching; Losses from soil systems; Water
management; Groundwater pollution; Soil texture
Abstract: Effects of furrow irrigation designs, water
management practices (irrigation scheduling, etc.), soil types
and pesticide parameters on pesticide leaching were simulated.
A hydraulic kinematic-wave irrigation model was used to
estimate water infiltration for alternative furrow lengths and
inflow rates. A one-dimensional simulation model then
simulated the movement of pesticides through soils following
furrow irrigation. Potential ground-water contamination by
pesticides can be reduced by an integrated use of the best
management practices (BMPs) such as careful selection and use
of pesticides, efficient furrow irrigation designs and
improved water management techniques (irrigation scheduling,
etc.). Procedures for designing an appropriate furrow
irrigation system for a particular site and pesticide, and
selecting pesticides for a particular site, crop and furrow
irrigation system are illustrated. These procedures are being
used to develop decision support computer models for
developing different BMPs for pesticide-agricultural
management decisions.
21 NAL Call. No.: GB701.W375 no.91-4055
Calibration, verification, and use of a steady-state stream
water-quality model for Monument and Fountain Creeks, east-
central Colorado. Kuhn, Gerhard
Pikes Peak Area Council of Governments, Geological Survey
(U.S.) Denver, CO : U.S. Dept. of the Interior, U.S.
Geological Survey : Books and Open-File Reports Section
[distributor],; 1991.
vii, 149 p. : ill. ; 28 cm. (Water-resources investigations
report ; 91-4055). Includes bibliographical references (p.
139-142).
Language: English
Descriptors: Water quality
22 NAL Call. No.: 290.9 AM32T
Characterization of macropore transport studied with the ARS
root zone water quality model.
Ahuja, L.R.; DeCoursey, D.G.; Barnes, B.B.; Rojas, K.W.
St. Joseph, Mich. : American Society of Agricultural
Engineers; 1993 Mar. Transactions of the ASAE v. 36 (2): p.
369-380; 1993 Mar. Includes references.
Language: English
Descriptors: Macropores; Movement in soil; Root zone flux;
Soil water; Water flow; Fertilizers; Pesticides; Simulation
models
Abstract: The ARS Root Zone Water Quality Model components
dealing with preferential water and chemical transport are
presented and used to study macropore flow and transport in a
silty clay loam soil. Macroporosity of the soil was assumed to
be 0.05% by volume, half of which was continuous and the rest
discontinuous. Two rainfall sequences with two initial soil
water contents, evaporation versus transpiration, macropore
radius ranging from 1.0 to 0.125 mm, and three different
chemicals were evaluated. Over a five-week period, weekly
rainfall of 25.4 mm in one hour, with soil water
redistribution and evaporation or transpiration occurring
between storms, generated no macropore flow when the soil was
initially dry (-1500 kPa). A slight amount of macropore flow
was generated under the same rainfall when the soil was
initially wet (-33 kPa). Doubling the weekly rainfall amount
and intensity generated macropore flow varying between 30 to
50% of rainfall depending on initial and boundary conditions.
Chemicals transported with this flow were 0.05 to 8% of the
surface-applied amount, depending on conditions and type of
chemical. A moderately adsorbed chemical (Atrazine) was the
most susceptible to macropore transport, followed in order by
a strongly adsorbed chemical (Prometryn), and a mobile
chemical (Nitrate). The flow entering the macropores was
partially absorbed by soil at progressively deeper depths; it
increased the water content of the root zone, and created a
tail of low concentrations in the soil chemical content
distributions. The macropore size had very little effect on
macropore flow and transport, but the smallest size pores
retarded the downward chemical movement by wall adsorption a
little more than the largest size pores. Surface evaporation
decreased macropore flow, soil water contents, and downward
chemical movement, but increased chemical content of the
macropore flow. Transpiration, on the other hand, decreased
both macropore flow and its chemical content. Thu
23 NAL Call. No.: HC79.E5E5
Classification and spatial mapping of riparian habitat with
applications toward management of streams impacted by nonpoint
source pollution. Delong, M.D.; Brusven, M.A.
New York, N.Y. : Springer-Verlag; 1991 Jul.
Environmental management v. 15 (4): p. 565-571; 1991 Jul.
Includes references.
Language: English
Descriptors: Idaho; Habitats; Riparian vegetation; Erosion;
Pollution; Information systems; Mapping; Watersheds; Farmland
24 NAL Call. No.: 56.8 J822
Classifying remotely sensed data for use in an agricultural
nonpoint-source pollution model.
Jakubauskas, M.E.; Whistler, J.L.; Dillworth, M.E.; Martinko,
E.A. Ankeny, Iowa : Soil and Water Conservation Society of
America; 1992 Mar. Journal of soil and water conservation v.
47 (2): p. 179-183; 1992 Mar. Includes references.
Language: English
Descriptors: Kansas; Water quality; Water pollution; Remote
sensing; Watersheds; Simulation models; Landsat; Thematic
mapper; Data collection
25 NAL Call. No.: SB610.W39
Combining computer simulation with physical simulation: an
attempt to validate turf runoff models.
Lin, J.C.; Graney, R.L.
Champaign, Ill. : The Society; 1992 Jul.
Weed technology : a journal of the Weed Science Society of
America v. 6 (3): p. 688-695; 1992 Jul. Paper presented at a
Symposium on the, "Role of Modeling in Regulatory Affairs," at
the Weed Science Society of America, February 4, 1991,
Louisville, Kentucky. Includes references.
Language: English
Descriptors: Agricultural chemicals; Pesticides; Simulation
models; Runoff; Risk; Aquatic environment; Calibration; Field
tests; Prediction
26 NAL Call. No.: 56.9 SO3
Comparison of models for describing the transport of dissolved
organic carbon in aquifer columns.
Jardine, P.M.; Dunnivant, F.M.; Selim, H.M.; McCarthy, J.F.
Madison, Wis. : The Society; 1992 Mar.
Soil Science Society of America journal v. 56 (2): p. 393-401;
1992 Mar. Includes references.
Language: English
Descriptors: Aquifers; Sediment; Organic matter; Carbon;
Transport processes; Adsorption; Sorption isotherms; Kinetics;
Contaminants; Movement in soil; Mathematical models;
Comparisons
Abstract: Dissolved organic carbon (DOC) is a reactive
constituent in aquifer and soil media and equilibrates between
the mobile aqueous phase and the immobile solid phase. Since
DOC is believed to accelerate the transport of associated
contaminants, yet is known to interact with aquifer and soil
material, our objective was to define and model those
processes governing DOC adsorption to porous media that may
affect the cotransport of contaminants. Column displacement
experiments of DOC through aquifer sediments were modeled with
various formulations of the convective-dispersive equation,
which considered time-dependent adsorption reactions and
linear or nonlinear adsorption processes. Batch equilibrium
adsorption isotherm and kinetic studies for DOC interaction
with the sediments were used to parameterize the transport
models. The equilibrium DOC-adsorption isotherm was nonlinear
and was adequately described by the Langmuir equation. The
adsorption of DOC to the aquifer sediment was also time
dependent and the batch results could be described by two
simultaneous reaction rates for solution concentrations
greater than or equal to 19 mg DOC L-1 and a slow reaction
rate for solution concentrations < 10 mg DOC L-1. Observed DOC
breakthrough curves (BTCs) with influent concentrations
greater than or equal to 10 mg DOC L-1, were adequately
modeled as two-site, non-linear adsorption processes, with DOC
interactions with both types of sites being time dependent.
Batch adsorption and kinetic parameters were generally
successful in describing DOC transport; however, the magnitude
of the initial batch rate coefficient was significantly larger
than that observed for the displacement experiments. The
extended tailing of the observed DOC BTCs was influenced more
by the slow, time-dependent adsorption of DOC during transport
than to the nonlinear features of the adsorption isotherms.
Observed DOC BTCs with influent concentrations < 10 mg DOC L-1
did not exhibit extensive tailing and were
27 NAL Call. No.: QH545.A1E58
Comparison of PRZM and GLEAMS computer model predictions with
field data for alachlor, metribuzin and norflurazon leaching.
Mueller, T.C.; Jones, R.E.; Bush, P.B.; Banks, P.A.
Elmsford, N.Y. : Pergamon Press; 1992.
Environmental toxicology and chemistry v. 11 (3): p. 427-436;
1992. Includes references.
Language: English
Descriptors: Alachlor; Norflurazon; Metribuzin; Herbicide
residues; Leaching; Computer simulation; Simulation models;
Soil depth; Sandy loam soils
28 NAL Call. No.: 292.8 J82 A
comprehensive surface-groundwater flow model.
Arnold, J.G.; Allen, P.M.; Bernhardt, G.
Amsterdam : Elsevier Scientific Publishers, B.V.; 1993 Feb.
Journal of hydrology v. 142 (1/4): p. 47-69; 1993 Feb.
Includes references.
Language: English
Descriptors: Texas; Groundwater; Groundwater flow; Groundwater
level; Surface water; Runoff; Flow; Stream flow; Watersheds;
Catchment hydrology; Land management; Climate; Vegetation;
Water management; Simulation models
Abstract: In this study, a simple groundwater flow and height
model was added to an existing basin-scale surface water
model. The linked model is: (1) watershed scale, allowing the
basin to be subdivided; (2) designed to accept readily
available inputs to allow general use over large regions; (3)
continuous in time to allow simulation of land management,
including such factors as climate and vegetation changes, pond
and reservoir management, groundwater withdrawals, and stream
and reservoir withdrawals. The model is described, and is
validated on a 471 km2 watershed near Waco, Texas. This linked
model should provide a comprehensive tool for water resource
managers in development and planning.
29 NAL Call. No.: 1.98 AG84
Computer model helps ensure clean water.
Cooke, L.
Washington, D.C. : The Service; 1991 Apr.
Agricultural research - U.S. Department of Agriculture,
Agricultural Research Service v. 39 (4): p. 10-12; 1991 Apr.
Language: English
Descriptors: Michigan; Groundwater pollution; Nitrates;
Leaching; Prevention; Computer simulation; Computer techniques
30 NAL Call. No.: SB610.W39
Computer models for fate assessment during the registration
process: data needs.
Behl, E.
Champaign, Ill. : The Society; 1992 Jul.
Weed technology : a journal of the Weed Science Society of
America v. 6 (3): p. 696-700; 1992 Jul. Paper presented at a
Symposium on the, "Role of Modeling in Regulatory Affairs," at
the Weed Science Society of America, February 4, 1991,
Louisville, Kentucky. Includes references.
Language: English
Descriptors: Pesticides; Registration; Simulation models;
Groundwater; Water quality
31 NAL Call. No.: GB701.W375 no.90-4200
Computer software for converting ground-water and water-
quality data from the National Water Information System for
use in a geographic information system.. Software for
converting data from NWIS for use in GIS
Scott, J. C.
Geological Survey (U.S.)
Oklahoma City, Okla. : U.S. Geological Survey ; Denver, Colo.
: Books and Open-File Reports [distributor],; 1991.
iv, 55 p. : ill. ; 28 cm. (Water-resources investigations
report ; 90-4200). Spine title: Software for converting data
from NWIS for use in GIS. Includes bibliographical references
(p. 38-39).
Language: English
Descriptors: Geographic information systems; Water
32 NAL Call. No.: 290.9 AM32T
Computing watershed storage probabilities from rainfall and
runoff data. Mills, W.C.; Thomas, A.W.; Dillard, A.L.; Snyder,
W.M.
St. Joseph, Mich. : American Society of Agricultural
Engineers; 1992 May. Transactions of the ASAE v. 35 (3): p.
891-897; 1992 May. Includes references.
Language: English
Descriptors: Rain; Runoff; Water conservation; Watersheds;
Mathematical models; Probability
Abstract: This article describes the development and
application of a computational procedure for obtaining
watershed storage probabilities that are corrected for bias
toward lower storage, which is inherent in storage values
computed directly from rainfall and runoff data. The developed
procedure makes use of rainfall and runoff data from
watersheds, and also incorporates probabilities for rainfall
needed to produce runoff for various storages. The procedure
is derived mathematically using basic probability concepts and
employs numerical integration and nonlinear least squares
optimization in the solution. The procedure is applied to
rainfall and runoff data collected from a Southern Piedmont
field watershed over a 10-year period during which a
conventional tillage system for crops was followed by two
successive conservation tillage systems. Results of the
application show that the developed computational procedure
performs adequately in providing bias-corrected watershed
storage probabilities that reflect effects of the three
cropping/tillage systems on watershed storage.
33 NAL Call. No.: TD426.J68
Conditional simulation of flow and transport.
Rogowski, A.S.; Wolf, J.K.; Simmons, D.E.
Amsterdam : Elsevier; 1991 Jan.
Journal of contaminant hydrology v. 7 (1/2): p. 95-121; 1991
Jan. Includes references.
Language: English
Descriptors: Groundwater pollution; Leachates; Movement in
soil; Groundwater recharge; Clay; Subsoil; Infiltration;
Spatial distribution; Simulation models; Spatial variation
34 NAL Call. No.: aSD11.A42
The conservation reserve program: effects on soil, water and
environmental quality.
Blackburn, W.H.; Newman, J.B.; Wood, J.C.
Fort Collins, Colo. : The Station; 1991 May.
General technical report RM - Rocky Mountain Forest and Range
Experiment Station, U.S. Department of Agriculture, Forest
Service (203): p. 27-36; 1991 May. Includes references.
Language: English
Descriptors: U.S.A.; Soil conservation; Erosion control;
Federal programs; Reserved areas; Simulation models;
Percolation; Evapotranspiration; Water erosion; Runoff
35 NAL Call. No.: TD420.A1E5
Convective transport of gases in moist porous media: effect of
absorption, adsorption, and diffusion in soil aggregates.
McCoy, B.J.; Rolston, D.E.
Washington, D.C. : American Chemical Society; 1992 Dec.
Environmental science & technology v. 26 (12): p. 2468-2476;
1992 Dec. Includes references.
Language: English
Descriptors: Soil pollution; Groundwater pollution; Volatile
compounds; Mathematical models
36 NAL Call. No.: TC401.W27 A
coupled rainfall-runoff and runoff-routing model for adaptive
real-time flood forecasting.
Habaieb, H.; Troch, P.A.; Troch, F.P. de
Hingham, Mass. : Kluwer Academic Publishers; 1991.
Water resources management v. 5 (1): p. 47-61; 1991. Includes
references.
Language: English
Descriptors: Belgium; Floods; Forecasting; Rain; Runoff;
Models; On line; Identification; Case studies
37 NAL Call. No.: 292.8 J82
Coupled simulations of water flow from a field-investigated
glacial till slope using a quasi-two-dimensional water and
heat model with bypass flow. Espeby, B.
Amsterdam : Elsevier Scientific Publishers, B.V.; 1992 Feb.
Journal of hydrology v. 131 (1/4): p. 105-132; 1992 Feb.
Includes references.
Language: English
Descriptors: Sweden; Glacial till soils; Forest soils;
Coniferous forests; Picea abies; Pinus sylvestris; Slopes;
Water flow; Macropore flow; Meltwater; Precipitation; Runoff;
Soil water retention; Saturated hydraulic conductivity;
Macropores; Soil temperature; Soil depth; Physical models;
Simulation models
Abstract: Substantial field investigations of soil physical
properties and stratification in a forested slope (10 degrees
slope) covered with glacial till revealed that macropores in
the form of old root channels as well as coarse structures in
the form of well-sorted layers dominate a very permeable upper
solid horizon. Rapid response and quick recessions during
snowmelt and heavy rains in 1986 were observed in the runoff
from the slope. Based on field tracer experiments it was found
that such macropores and macrostructures played an important
role on these occasions. In order to verify these findings
one-dimensional water and heat models were coupled in a serial
manner to simulate the formation of runoff from the slope,
using a quasi-two-dimensional approach. Both a strict Darcian
concept and a Darcian concept with a simple bypass flow
concept introduced were tested. The drainage gradient in the
model was made equal with the angle of the slope. Coupled
slope simulations, with water retention properties and
hydraulic conductivities taken from three different levels on
the slope, indicated that the conditions in the lower region
of the slope were most important in explaining the discharge
rate. With a shallow groundwater table in the lower region of
the slope and low hydraulic conductivity of the deeper layers,
rapid water flows are routed to the uppermost layers where the
conductivity is higher. Most of the flow is well described by
Richards' equation, although smaller peaks cannot be
represented for small rain events, when the measured runoff
and recession showed a more rapid response than that
simulated, however, the introduction of a simple bypass flow
improved the ability of the model to simulate the
observations. Much of the simulated surface runoff generated
in the Darcian simulation during the winter of 1986, could be
diverted through a frost layer in the humus horizon and in the
humus-impregnated mineral horizon with a silty-sand character,
down to a more conductiv
38 NAL Call. No.: QH540.J6
Coupling groundwater contamination with economic returns when
applying farm pesticides.
Hoag, D.L.; Hornsby, A.G.
Madison, Wis. : American Society of Agronomy; 1992 Oct.
Journal of environmental quality v. 21 (4): p. 579-586; 1992
Oct. Includes references.
Language: English
Descriptors: North Carolina; Groundwater pollution;
Methodology; Pesticides; Usage; Economic impact; Returns;
Profitability; Environmental impact; Glycine max; Weed
control; Costs; Crop yield; Weed competition; Leaching;
Simulation models
Abstract: A methodology is presented that permits
simultaneous consideration of the economics of production and
groundwater contamination hazard of pesticide use. An example
is constructed for weed control in soybean (Glycine max L.)
production at Clayton, NC. A cost/groundwater hazard frontier
is developed that can be used to identify and illustrate the
cost tradeoffs of selecting alternative weed control
strategies that reduce the risk of adverse health effects from
drinking contaminated groundwater. The methodology relies on
models to estimate costs, crop yields, pest competition, and
leaching of pesticides; thus, its applicability depends on
availability of local data and appropriately validated models
for the site considered. The cost/groundwater hazard frontier
provides a useful decision aid to assist pesticide users in
making cost-effective and environmentally favorable production
decisions. It is also useful in evaluating policy or the value
of new pest control technologies, as it indicates a farmer's
ability to substitute alternatives for currently used
practices.
39 NAL Call. No.: 381 J8224
Criteria to assess when biodegradation is kinetically limited
by intraparticle diffusion and sorption.
Chung, G.Y.; McCoy, B.J.; Scow, K.M.
New York, N.Y. : John Wiley & Sons; 1993 Mar15.
Biotechnology and bioengineering v. 41 (6): p. 625-632; 1993
Mar15. Includes references.
Language: English
Descriptors: Soil flora; Microbial degradation; Pollutants;
Transport processes; Diffusion; Sorption; Desorption; Polluted
soils; Soil pollution; Mathematical models; Bioremediation
Abstract: To determine when intraparticle diffusion and
sorption can influence the rate of biodegradation, we consider
the biodegradation of a pollutant diffusing into or out of
porous aggregates suspended in a liquid medium, where the
reactant is metabolized by bacteria. The pollutant that
diffuses into the aggregates obeys a sorption-desorption
equilibrium isotherm at sites on inner pore surfaces. The
governing partial differential equations for the transient
process describe (a) the local equilibrium sorption-desorption
and the diffusion of the pollutant in the porous aggregate,
(b) the mass transfer of the pollutant from the external
surface of the spherical aggregates to the reaction medium,
and (c) the biodegradation of the pollutant in the external
medium. Illustrative calculations are presented for a linear
sorption isotherm and first-order biodegradation kinetics. A
dimensionless group, comprised of the diffusion coefficient,
biodegradation rate coefficient, aggregate characteristic
length (radius), and adsorption capacity, serves as a
criterion for determining when intraparticle diffusion
resistance can be ignored. The model provides a realistic
description of experimental data for biodegradation of a
pollutant subject to intraparticle diffusion and sorption.
40 NAL Call. No.: TD420.A1P7
DBAPE--a database and model parameter analysis system for
agricultural soils to support water quality management.
Imhoff, J.C.; Carsel, R.F.; Kittle, J.L. Jr; Hummel, P.R.
Oxford : Pergamon Press; 1991.
Water science and technology : a journal of the International
Association on Water Pollution Research and Control v. 24 (6):
p. 331-337; 1991. In the series analytic: Watermatex '91 /
edited by T.O. Barnwell, P.J. Ossenbruggen and M.B. Beck.
Proceedings of the "Second International Conference on Systems
Analysis in Water Quality Management," June 3-6, 1991, Durham,
New Hampshire. Includes references.
Language: English
Descriptors: Soil properties; Water quality; Management;
Agricultural soils; Computer software; Subsurface runoff;
Models; Databases
41 NAL Call. No.: QH540.J6
Degradation and transport of dicamba in a clay soil.
Comfort, S.D.; Inskeep, W.P.; Macur, R.E.
Madison, Wis. : American Society of Agronomy; 1992 Oct.
Journal of environmental quality v. 21 (4): p. 653-658; 1992
Oct. Includes references.
Language: English
Descriptors: Dicamba; Clay soils; Degradation; Leaching; Soil
water movement; Soil temperature; Persistence; Half life;
Precipitation; Irrigation scheduling; Simulation models
Abstract: Dicamba (3,6-dichloro-2-methoxybenzoic acid) has
been identified as one of five pesticides present in Montana
groundwaters. We determined the effects of degradation and
time of water application on the transport of dicamba in a
Lohmiller clay soil (fine, montmorillonitic, mesic Ustic
Torrifluvent). Carbon 14-labeled dicamba was surface applied
(0.35 kg ha-1) to disturbed soil columns (5.0 cm diam; 29 cm
length) previously conditioned with 3 mM CaCl2. The columns
were allowed to incubate (23.5 degrees C) in triplicate for 0,
14, 21, 28, and 42 d. Following incubation, the columns were
attached to a vacuum chamber containing a fraction collector
and leached with 3 mM CaCl2 under unsaturated conditions.
Dicamba breakthrough curves were determined for each
incubation period. The percentage of dicamba recovered in the
column effluent decreased from 85% (of total applied) after no
incubation to 9.5% after 42 d of incubation. The decline of
dicamba in the effluent coincided with an accumulation of
dichlorosalicyclic acid at the soil surface. Dicamba half-
lives determined under batch conditions were 23.5 d at 28
degrees C, 38 d at 20 degrees C, and 151 d at 12 degrees C,
and were all higher than the half-life estimated from the
decrease in column effluent concentrations over time (13.5 d).
The simulation model, LEACHM, was used to predict transport of
dicamba after the different incubation periods. LEACHM
adequately estimated the mass of dicamba leached, but
underestimated the maximum dicamba concentrations observed in
the effluent. Both simulated and observed results indicated
that the transport of dicamba can be greatly reduced if
sufficient degradation of dicamba is allowed to occur before
irrigation or precipitation.
42 NAL Call. No.: QC851.J62 A
description of rainfall interception over large areas.
Eltahir, E.A.B.; Bras, R.L.
Boston, MA : American Meteorological Society, c1988-; 1993
Jun. Journal of climate v. 6. (6): p. 1002-1008; 1993 Jun.
Includes references.
Language: English
Descriptors: Rain; Ground vegetation; Canopy; Drainage; Runoff
water; Interception; Evaporation; Models; Climatic factors
Abstract: A new scheme is developed for describing
interception at spatial scales comparable to the typical
resolution of climate models. The scheme is based on the
Rutter model of interception and statistical description of
the subgrid-scale spatial variability of canopy storage and
rainfall. The interception loss simulated by the new scheme is
significantly smaller than those simulated by other schemes
that do not include considerations for spatial variability.
The explanation of this result is partly in the enhancement of
spatially averaged canopy drainage due to the large local
drainage from the few buckets of large canopy storage. The
relative reduction in interception loss simulated by the new
scheme may explain the overestimation of interception loss by
climate models that do not include the effects of spatial
variability on interception processes.
43 NAL Call. No.: TD403.G7
Design and evaluation of a mesoscale model vadose zone and
ground-water system.
Lawrence, J.R.; Zanyk, B.N.; Hendry, M.J.; Wolfaardt, G.M.;
Robarts, R.D.; Caldwell, D.E.
Dublin, Ohio : Ground Water Pub. Co; 1993 May.
Ground water v. 31 (3): p. 446-455; 1993 May. Includes
references.
Language: English
Descriptors: Groundwater pollution; Soil pollution;
Contaminants; Movement in soil; Chemical degradation;
Microbial degradation; Models; Agricultural chemicals
Abstract: A mesoscale model soil and ground-water system was
constructed and instrumented to study physical, chemical, and
microbial processes, including transport and degradation of
contaminants. The model system was 4.6 m in height by 2.4 m in
diameter and contained up to 65 tonnes of soil and geologic
materials. The model was filled with Ap (11 cm), B (20 cm), Cl
and C2 (369 cm) horizons; the water table was 3.3 m from the
soil surface. A rain simulation system applied uniform
coverage of rain and/or chloride tracer to the model. Sampling
of soil, sediment, pore waters, and gas phase was carried out
using a series of in situ collectors and sampling ports. Major
anions, metals, pH, alkalinity, CO2, N2, O2, CH4, microbial
numbers, microbial biomass and heterotrophic potential (14 C-
amino-acid uptake) were monitored over time (120 days) and
depth. The system approached steady state with respect to
solution chemistry and gases after approximately 60-70 days.
During this interval, carbon dioxide rose from atmospheric to
3-5% of total gas volume measured at each sampling depth above
the water table. Physical, chemical, and biological conditions
in the model system after the initial 120 days were comparable
to those reported for vadose and saturated zones during field
studies on shallow phreatic aquifers. These results indicated
that the mesoscale model preserved many of the features of
natural systems while providing controlled conditions for
studies such as evaluating the fate, and ground-water
contamination potential, of agricultural and industrial
chemicals.
44 NAL Call. No.: TD201.A4
Design of optimal pump-and-treat strategies of contaminated
groundwater remediation using the simulated annealing
algorithm.
Kuo, C.H.; Michel, A.N.; Gray, W.G.
Essex : Elsevier Science Publishers Ltd; 1992.
Advances in water resources v. 15 (2): p. 95-105; 1992.
Includes references.
Language: English
Descriptors: Groundwater pollution; Problem solving; Pumps;
Placement; Optimization methods; Hydraulics; Constraints;
Simulation models; Algorithms
45 NAL Call. No.: TD403.G7
Designing a nitrate monitoring program in a heterogeneous,
carbonate aquifer. Smith, R.T.; Ritzi, R.W. Jr
Dublin, Ohio : Ground Water Pub. Co; 1993 Jul.
Ground water v. 31 (4): p. 576-584; 1993 Jul. Includes
references.
Language: English
Descriptors: Ohio; Aquifers; Carbonates; Hydraulic
conductivity; Finite element analysis; Simulation models;
Nitrates; Movement in soil; Zea mays; Glycine max; Rotations;
Groundwater pollution
46 NAL Call. No.: 292.9 AM34
Determination of best timing for poultry waste disposal: a
modeling approach. Edwards, D.R.; Daniel, T.C.; Marbun, O.
Bethesda, Md. : American Water Resources Association; 1992
May. Water resources bulletin v. 28 (3): p. 487-494; 1992 May.
Includes references.
Language: English
Descriptors: Arkansas; Poultry manure; Waste disposal;
Application to land; Application date; Timing; Surface water;
Runoff water; Water quality; Nitrogen; Phosphorus; Losses from
soil systems; Grasses; Crop production; Crop yield
Abstract: Confined production of poultry results in
significant volumes of waste material which are typically
disposed of by land application. Concerns over the potential
environmental impacts of poultry waste disposal have resulted
in ongoing efforts to develop management practices which
maintain high quality of water downstream of disposal areas.
The timing of application to minimize waste constituent losses
is a management practice with the potential to ensure high
quality of streams, rivers, and lakes downstream of receiving
areas. This paper describes the development and application of
a method to identify which time of year is best, from the
standpoint of surface water quality, for land application of
poultry waste. The procedure consists of using a mathematical
simulation model to estimate average nitrogen and phosphorus
losses resulting from different application timings, and then
identifying the timings which minimize losses of these
nutrients. The procedure was applied to three locations in
Arkansas, and three different criteria for optimality of
application timing were investigated. One criterion was
oriented strictly to water quality, one was oriented only to
crop production, and the last was a combination. The criteria
resulted in different windows of time being identified as
optimal. Optimal windows also varied with location of the
receiving area. The results indicate that it is possible to
land-apply poultry waste at times which both minimize nutrient
losses and maximize crop yield.
47 NAL Call. No.: SB951.P47
Development and validation of a modified fugacity model of
pesticide leaching from farmland.
Brooke, D.; Matthiessen, P.
Essex : Elsevier Applied Science Publishers; 1991.
Pesticide science v. 31 (3): p. 349-361; 1991. Includes
references.
Language: English
Descriptors: England; Mecoprop; Simazine; Concentration;
Leaching; Measurement; Models; Monitoring; Soil properties;
Water pollution; Agricultural soils
Abstract: To test whether a simple model could provide
reasonable quantitative estimates of chemical concentrations
in a dynamic situation, Mackay's fugacity model was adapted to
represent an agricultural field. The intention was to
determine the extent of modification required to obtain
reasonable agreement with experimental results, or indeed if
such agreement could be achieved. The validity of the model
was tested at Rosemaund Experimental Husbandry Farm in
Herefordshire, where the chemical input and output could be
monitored and meteorological and other parameters measured
regularly. Results from monitoring concentrations of two
pesticides at this site in recent years. and changes that have
been made to the model in attempting to fit the observed
behaviour are described.
48 NAL Call. No.: QH540.J6
Development of a database and model parameter analysis system
for agricultural soils.
Carsel, R.F.; Imhoff, J.C.; Kittle, J.L. Jr; Hummel, P.R.
Madison, Wis. : American Society of Agronomy; 1991 Jul.
Journal of environmental quality v. 20 (3): p. 642-647; 1991
Jul. Includes references.
Language: English
Descriptors: Water quality; Water management; Databases;
Computer software; Water flow
Abstract: An interactive computer program was developed for
obtaining soils data for geographic analyses and estimation of
soil water retention data for simplistic and classical water
flow models. The soils data base contains 8080 soil series
identified from the USDA-SCS. The data are organized in
sequential files that contain textural, morphological crop
support, and geographical location (at a county level) and
density (ha/county). The computer program allows the
exploration of the database, clarifying the impact of data on
modeled processes, screening geographically based data to
identify potential sites for model application or testing, and
developing initial guidance on alternative water quality
management strategies. The program allows the display of data
in the form of generated reports and production of geographic
maps and plots of soil water functional relationships.
Indirect methods are used in the program for estimating soil
water retention characteristics using textural information
from the soil data base. Estimates of variability can be
developed within a soil series or among series by using
reported ranges for textural information on each series
contained in the soil database.
49 NAL Call. No.: S592.7.A1S6
Dispersion effect on the apparent nitrogen isotope
fractionation factor associated with denitrification in soil;
evaluation by a mathematical model. Kawanishi, T.; Hayashi,
Y.; Kihou, N.; Yoneyama, T.; Ozaki, Y. Exeter : Pergamon
Press; 1993 Mar.
Soil biology and biochemistry v. 25 (3): p. 349-354; 1993 Mar.
Includes references.
Language: English
Descriptors: Denitrification; Quantitative analysis;
Agricultural soils; Solutes; Dispersion; Transport processes;
Soil water; Water flow; Mathematical models; Nitrate;
Groundwater pollution
Abstract: An analytical model is constructed to investigate
the effect of dispersion on the apparent 15N/14N fractionation
factor associated with denitrification in soil. The steady
input of solute with a fixed isotope ratio, uniform flow of
the solute, and the first-order reaction for each isotope are
assumed, and the relationship between the concentration
distribution and the change of isotope ratio in the steady
state is examined. The only dimensionless parameter, kl4ND/v2,
the product of the first-order reaction rate constant and the
dispersion coefficient divided by the square of the
superficial velocity, determines the effect of dispersion, and
if its value is larger than 0.01, the dispersion will affect
the apparent isotope fractionation factor. As kl4ND/v2
increases, the effect becomes more prominent, and when it
approaches infinity, the ratio of the apparent per mille
enrichment factor to the true one, (alpha ap-1)/(alpha tr-1),
reaches 0.5.
50 NAL Call. No.: GB701.W375 no.93-4015
Documentation of geographic-information-system coverages and
data-input files used for analysis of the geohydrology of the
Virginia Coastal Plain.. Documentation of geographic
information system coverages and data input files used for
analysis of the geohydrology of the Virginia Coastal Plain
Focazio, Michael J.; Samsel, Theodore B.
Geological Survey (U.S.),Hampton Roads Planning District
Commission (Va.),Virginia Water Control Board
Richmond, Va. : U.S. Geological Survey ; Denver, CO : Books
and Open-File Reports Section [distributor],; 1993; I
19.42/4:93-4015.
vi, 53 p. : maps ; 28 cm. (Water-resources investigations
report ; 93-4015). Shipping list no.: 93-0451-P. Includes
bibliographical references (p. 11).
Language: English; English
Descriptors: Hydrogeology; Geographic information systems
51 NAL Call. No.: 292.8 W295 A
dual-porosity model for simulating the preferential movement
of water and solutes in structured porous media.
Gerke, H.H.; Van Genuchten, M.T.
Washington, D.C. : American Geophysical Union; 1993 Feb.
Water resources research v. 29 (2): p. 305-319; 1993 Feb.
Includes references.
Language: English
Descriptors: Transport processes; Solutes; Water flow;
Saturated flow; Transient flow; Leaching; Porous media;
Physicochemical properties; Deterministic models; Mathematical
models; Equations
Abstract: A one-dimensional dual-porosity model has been
developed for the purpose of studying variably saturated water
flow and solute transport in structured soils or fractured
rocks. The model involves two overlaying continua at the
macroscopic level: a macropore or fracture pore system and a
less permeable matrix pore system. Water in both pore systems
is assumed to be mobile. Variably saturated water flow in the
matrix as well as in the fracture pore system is described
with the Richards' equation, and solute transport is described
with the convection-dispersion equation. Transfer of water and
solutes between the two pore regions is simulated by means of
first-order rate equations. The mass transfer term for solute
transport includes both convective and diffusive components.
The formulation leads to two coupled systems of nonlinear
partial differential equations which were solved numerically
using the Galerkin finite element method. Simulation results
demonstrate the complicated nature of solute leaching in
structured, unsaturated porous media during transient water
flow. Sensitivity studies show the importance of having
accurate estimates of the hydraulic conductivity near the
surface of soil aggregates or rock matrix blocks. The proposed
model is capable of simulating preferential flow situations
using parameters which can be related to physical and chemical
properties of the medium.
52 NAL Call. No.: 100 C12CAG
Dupuit-Forchheimer approximation may underestimate groundwater
flow to San Joaquin River.
Grismer, M.E.; Rashmawi, E.A.
Oakland, Calif. : Division of Agriculture and Natural
Resources, University of California; 1993 Jan.
California agriculture v. 47 (1): p. 12, 13-15; 1993 Jan.
Language: English
Descriptors: California; Groundwater flow; River water; Water
quality; Water management; Salinity; Estimation; Water table;
Errors; Mathematical models
53 NAL Call. No.: GB746.W33
Dynamic-probabilistic models for the formation of rainfall and
snowmelt runoff.
Kuchment, L.S.; Gel'fan, A.N.
New York, N.Y. : Consultants Bureau; 1992 May.
Water resources v. 18 (4): p. 335-343; 1992 May. Translated
from: Vodnye Resursy, v. 18 (4), 1991, p. 5-14, (GB746.V55).
Includes references.
Language: English; Russian
Descriptors: U.S.S.R.in europe; Rain; Meltwater; Floods;
Runoff water; Watersheds; Forest steppe; Zoning; Probabilistic
models; Dynamic models; Physical models; Mathematical models;
Weather data
54 NAL Call. No.: HD101.S6
Economic impacts of chemical use reduction on the South.
Taylor, C.R.; Penson, J.B. Jr; Smith, E.G.; Knutson, R.D.
Experiment, Ga. : The Association; 1991 Jul.
Southern journal of agricultural economics - Southern
Agricultural Economics Association v. 23 (1): p. 15-23; 1991
Jul. Discussion by J.R. Schaub, p. 25-26. Includes
references.
Language: English
Descriptors: Southern states of U.S.A.; Agricultural
chemicals; Pesticide residues; Water quality; Groundwater;
Contamination; Food safety; Agricultural policy; Models;
Economic impact; Income
55 NAL Call. No.: HD1.A3
The economics of water harvesting and supplementary irrigation
in the semi-arid tropics of India.
Pandey, S.
Essex : Elsevier Applied Science Publishers; 1991.
Agricultural systems v. 36 (2): p. 207-220; 1991. Includes
references.
Language: English
Descriptors: Madhya pradesh; Soybeans; Wheat; Water
harvesting; Irrigation; Cropping systems; Semiarid zones;
Agricultural regions; Economic evaluation; Feasibility; Risk;
Simulation models; Soil water balance; Yield response
functions; Water relations; Decision making; Rain; Runoff
water
56 NAL Call. No.: 56.8 SO3
The effect of soil P sorption kinetics on parameters used for
modeling P uptake.
Shnek, M.; Shaviv, A.; Ravina, I.
Baltimore, Md. : Williams & Wilkins; 1991 May.
Soil science v. 151 (5): p. 333-342; 1991 May. Includes
references.
Language: English
Descriptors: Calcareous soils; Soil physics; Phosphorus;
Sorption; Kinetics; Diffusion models; Desorption; Mathematical
models; Soil solution; Equilibrium; Buffering capacity;
Nutrient uptake; Prediction; Equations; Solubility; Nutrient
availability; Transport processes
57 NAL Call. No.: 56.8 SO3
The effect of soil properties on phosphorus sorption by
everglades histosols. Porter, P.S.; Sanchez, C.A.
Baltimore, Md. : Williams & Wilkins; 1992 Nov.
Soil science v. 154 (5): p. 387-398; 1992 Nov. Includes
references.
Language: English
Descriptors: Florida; Histosols; Agricultural soils;
Phosphorus; Sorption; Movement in soil; Leaching; Losses from
soil systems; Soil chemistry; Soil properties; Water
pollution; Indexes; Models
58 NAL Call. No.: 292.8 J82
The effect of transverse dispersion on solute transport in
soils. Leij, F.J.; Dane, J.H.
Amsterdam : Elsevier Scientific Publishers, B.V.; 1991 Jan.
Journal of hydrology v. 122 (1/4): p. 407-422; 1991 Jan.
Includes references.
Language: English
Descriptors: Solutes; Transport processes; Horizontal flow;
Two dimensional flow; Transverse distribution; Permeability;
Simulation; Mathematical models
Abstract: Most theoretical and experimental investigations of
solute transport involve one-dimensional problems (i.e. soil
column studies), whereas in reality many soil pollution
problems concern transport and flow in more than one
dimension. This study investigates two-dimensional transport,
with emphasis on the contribution of transverse dispersion to
solute transport. Three problems were studied with a finite
element code. The first problem involved one-dimensional flow
parallel to the interface of two layers with differing pore-
water velocity. The early arrival of the solute at the end of
the low-permeability layer and the increase-in solute
spreading for both layers, as a result of transverse
dispersion, were demonstrated. The two other problems
concerned transport of a pollutant from a point source and a
diffuse source, respectively, located at the soil surface. The
magnitude of the transverse dispersion coefficient influenced
the region to which the pollution extended as well as the
intensity of the pollution.
59 NAL Call. No.: 292.8 W295
The effect of vertical soil heterogeneity on field scale
solute flux. Destouni, G.
Washington, D.C. : American Geophysical Union; 1992 May.
Water resources research v. 28 (5): p. 1303-1309; 1992 May.
Includes references.
Language: English
Descriptors: Solutes; Transport processes; Flow; Saturated
hydraulic conductivity; Soil depth; Stochastic models
Abstract: Vertical heterogeneity is incorporated in a
stochastic transport model, in which the soil is viewed as
consisting of an ensemble of essentially vertical, independent
stream tubes. The saturated hydraulic conductivity in each
stream tube is defined as the vertical average of the
corresponding point random process. The statistics of the
vertically averaged hydraulic conductivity and the resulting
statistics of solute travel time are depth dependent. The
evolution of the field scale breakthrough curve with depth is
analyzed in terms of the first two moments of solute travel
time to an arbitrary depth below the soil surface. The arrival
time of the solute center of mass, quantified by the expected
travel time, grows linearly with depth also for vertically
heterogeneous soil. The temporal solute spreading around its
center, quantified by the travel time variance, may exhibit a
compression-expansion that is qualitatively analogous to the
solute plume behavior in the studies of Butters and Jury
(1989), Russo (1991), and Ellsworth and Jury (1991). The
relative solute spreading, quantified by the travel time
coefficient of variation, decreases with increasing depth.
60 NAL Call. No.: QH540.J6
Effects of climatic variations over 11 years on nitrate-
nitrogen concentrations in the Raccoon River, Iowa.
Lucey, K.J.; Goolsby, D.A.
Madison, Wis. : American Society of Agronomy; 1992 Jan.
Journal of environmental quality v. 22 (1): p. 38-46; 1992
Jan. Includes references.
Language: English
Descriptors: Iowa; Nitrate nitrogen; Drinking water; Seasonal
variation; Precipitation; Stream flow; Water quality; Water
pollution; Nitrogen fertilizers; Mathematical models
Abstract: Nitrate-nitrogen (NO3-N) concentrations at public
water-supply intakes on the Des Moines and Raccoon Rivers in
Iowa exceeded the maximum contaminant level (MCL) of 10 mg L-1
for public water supplies established by the USEPA for
extended periods of time from March through early August 1990.
The excessive NO3-N levels followed 2 yr of less than normal
precipitation in 1988 and 1989. The largest daily NO3-N load
(771 t) transported during the last 17 yr in the Raccoon River
occurred in June 1990. The streamflow hydrograph for the
Raccoon River for March 1990 prior to seasonal fertilizer
application indicates that high NO3-N concentrations
characterize the recession side of the hydrograph. High NO3-N
concentrations in streamflow persisted as streamflow decreased
to baseflow conditions. This implies that substantial
quantities of NO3-N were being leached from the soil and
transported by subsurface flow during early 1990. A multiple
linear-regression model was developed to predict NO3-N
concentrations in the Raccoon River from readily-obtainable
streamflow and climatic data. The four-variable model
explained about 70% of the variability in the concentration of
NO3-N. The mean streamflow for the previous 7-d period
accounted for about 50% of the total variability.
61 NAL Call. No.: 290.9 AM32T
Effects of pesticide, soil, and rainfall characteristics on
potential pesticide loss by percolation--a GLEAMS simulation.
Truman, C.C.; Leonard, R.A.
St. Joseph, Mich. : American Society of Agricultural
Engineers; 1991 Nov. Transactions of the ASAE v. 34 (6): p.
2461-2468; 1991 Nov. Includes references.
Language: English
Descriptors: Georgia; Pesticides; Percolation; Leaching;
Losses from soil systems; Water pollution; Groundwater;
Computer simulation; Zea mays
Abstract: Potential pesticide loss in soil percolate is
influenced by pesticide persistence and sorption by soil
constituents (organic matter). Pesticide persistence,
expressed as half-life (t1/2), changes with soil depth as
microbial activity and soil properties change. Little is
known, however, how these changes influence potential
pesticide transport out of the root zone. Objectives of this
study were to investigate relative differences in potential
pesticide losses from the root zone by percolation due to 1)
different soil surface and subsurface textures and pesticide
t1/2, and 2) interactions between pesticide t1/2 arid timing
of rainfall after pesticide application. The GLEAMS
(Groundwater Loading Effects of Agricultural Management
Systems) model and a 50-year historical rainfall record at
Tifton, Georgia, were used to simulate pesticide losses by
percolation from three soils ranging in surface texture from
sand to sandy clay loam. Hypothetical pesticides had surface
t1/2 of 5, 15, 30, and 60 d and a range of subsurface t1/2
(2.5-360 d), and were applied to continuous corn (Zea maize,
L.) at 2 kg ha-1 as surface spray at planting each year on 1
April. Simulated pesticide losses by percolation increased
with increased surface and subsurface t1/2, and decreased with
increased KOC (adsorption constant based on soil organic
matter) values. Potential pesticide leaching was greatest for
Lakeland sand and least for Greenville sandy clay loam.
Rainfall timing affected simulated pesticide loss by
percolation, especially for nonpersistent pesticides. For
short pesticide t1/2 (0-5 d), excessive rainfall events within
1 t1/2 were largely responsible for simulated pesticide loss
by percolation. Results indicate that changes in pesticide
t1/2 in surface and subsurface horizons of different soils
influence potential pesticide leaching from the root zone, and
models (i.e., GLEAMS) can be used to provide comparative
analysis of soil-pesticide-climate interactions. For example,
dependi
62 NAL Call. No.: 292.8 W295
Effects of rainfall, vegetation, and microtopography on
infiltration and runoff.
Dunne, T.; Zhang, W.; Aubry, B.F.
Washington, D.C. : American Geophysical Union; 1991 Sep.
Water resources research v. 27 (9): p. 2271-2285; 1991 Sep.
Includes references.
Language: English
Descriptors: Soil water; Infiltration; Runoff; Rain; Hill
grasslands; Slope; Plant density; Hydraulic conductivity;
Mathematical models
Abstract: Apparent, or effective, infiltration rates on
grassland hillslopes vary with rainfall intensity and flow
depth because of the interaction between rainfall, runoff, and
vegetated microtopography. The higher parts of the
microtopography are occupied by greater densities of
macropores and therefore have much greater hydraulic
conductivities than the intervening microdepressions. On short
hillslopes and plots the apparent infiltration rate is simply
the spatial average of the saturated and unsaturated
conductivities of this surface. The proportion of the surface
which is saturated and the value to which the unsaturated
conductivity is raised depends on the rainfall intensity. On
longer hillslopes the downslope increase in flow depth in
microtopographic depressions progressively inundates more
permeable, vegetated mounds so that the hydraulic conductivity
of a greater proportion of the surface is raised to its
saturated value. For this reason the apparent infiltration
rate increases downslope, even in the absence of spatial
trends in any of the surface characteristics that affect
infiltration. Apparent, or effective, infiltration rate
depends on hillslope length. Consequently, steady state
discharge does not increase linearly with distance downslope.
These two fundamental relationships between infiltration,
rainfall intensity, and runoff are analyzed on the basis of
sprinkling-infiltrometer measurements and a mathematical
model.
63 NAL Call. No.: 292.8 W295
Effects of soil heterogeneity on pesticide leaching to
groundwater. Zee, S.E.A.T.M. van der; Boesten, J.J.T.I.
Washington, D.C. : American Geophysical Union; 1991 Dec.
Water resources research v. 27 (12): p. 3051-3063; 1991 Dec.
Includes references.
Language: English
Descriptors: Pesticides; Groundwater; Leaching; Hydrodynamic
dispersion; Sorption; Transformation; Uptake; Physicochemical
properties; Spatial variation; Stochastic models; Monte carlo
method
Abstract: Pesticide leaching was simulated numerically
assuming Freundlich adsorption, first-order transformation and
passive plant uptake, taking transient flow, hydrodynamic
dispersion, and depth as well as temperature dependence of
(bio)chemical parameters into account. The dependency of the
leached fraction on sorption and transformation parameters
appeared to be in good general agreement with the model
developed by Jury et al. (1987). We incorporated spatial
variability of (bio)chemical parameters into the piston flow
model and showed how spatial variability may be accounted for
without having to resort to demanding Monte Carlo techniques.
Such spatial variability affects the leached fraction
significantly. The data requirement of the simple stochastic
model is small and the versatility relatively high. For
parameter values often not of prime practical interest for
pesticide screening this model fails. Considering transport by
convection and dispersion in the semi-infinite domain, this
spatial variability can be easily accounted for using
parameter ranges for which our original analytical model for
spatially variable piston transport failed. In this revised
model, hydrodynamic dispersion, preferential flow, and spatial
variability of transformation, sorption and soil thickness are
dealt with in a similar fashion, while both correlation or the
absence of correlation of parameters can be incorporated
through an approximation of apparent residence time variance.
64 NAL Call. No.: QH540.J6
Effects of spatial accumulation of runoff on watershed
response. Garbrecht, J.
Madison, Wis. : American Society of Agronomy; 1991 Jan.
Journal of environmental quality v. 20 (1): p. 31-35; 1991
Jan. Literature review. Includes references.
Language: English
Descriptors: Watersheds; Drainage; Hydrology; Rain; Runoff;
Simulation models
Abstract: The drainage network accumulates upstream
subwatershed runoff into a single downstream response, with
runoff accumulating at network junctions. The effects of this
accumulation on the magnitude and spatial variability of the
downstream response are reviewed for simplified boundary
conditions. Runoff parameters are runoff depth and
corresponding unit area peak runoff rate. At the subwatershed
level these parameters are referred to as d and q,
respectively, and they vary from one subwatershed to another.
At a downstream location, after accumulation by the drainage
network, corresponding parameters are referred to as D and Q.
Equations expressing the effects of runoff accumulation are
formulated and discussed for uniform rainfall conditions. The
review shows that the effects of runoff accumulation gain in
importance as the number of upstream subwatersheds and the
size of the watershed increase in the downstream direction.
The accumulation process cancels extreme values of d and q to
yield a representative D and Q value for the entire upstream
drainage area. The impact of individual d and q values on the
downstream D and Q values in the channel diminishes as the
number of upstream subwatersheds increases. This results in a
decrease in the spatial variability of D and Q in the
downstream direction. The review suggests that the role of
spatial variability of upstream d and q in the determination
of downstream D and Q diminishes as watershed size increases.
However, nonuniform rainfall distributions and storm movement
may overshadow the effects of runoff accumulation when
watershed size increases beyond the size of the storm.
65 NAL Call. No.: 325.28 P56
Effects of suspended particle size and concentration on
reflectance measurements.
Bhargava, D.S.; Mariam, D.W.
Bethesda, Md. : American Society of Photogrammetry and Remote
Sensing; 1991 May.
Photogrammetric engineering and remote sensing v. 57 (5): p.
519-529; 1991 May. Includes references.
Language: English
Descriptors: Soil types; Suspensions; Particle size; Sediment;
Concentration; Reflectance; Responses; Prediction; Models;
Turbidity; Water quality; Equations; Remote sensing
66 NAL Call. No.: TD403.G7
Effects of waste-water irrigation on aqueous geochemistry near
Paris, Texas. Tedaldi, D.J.; Loehr, R.C.
Dublin, Ohio : Ground Water Pub. Co; 1992 Sep.
Ground water v. 30 (5): p. 709-719; 1992 Sep. Includes
references.
Language: English
Descriptors: Texas; Waste water; Irrigation; Long term
experiments; Groundwater; Water quality; Soil chemistry;
Geochemistry; Prediction; Thermodynamics; Equilibrium; Models;
Aquifers; Saline water; Recharge; Infiltration; Hydraulic
conductivity
67 NAL Call. No.: TD420.A1E5
Elution of aged and freshly added herbicides from a soil.
Pignatello, J.J.; Ferrandino, F.J.; Huang, L.Q.
Washington, D.C. : American Chemical Society; 1993 Aug.
Environmental science & technology v. 27 (8): p. 1563-1571;
1993 Aug. Includes references.
Language: English
Descriptors: Connecticut; Soil pollution; Herbicide residues;
Atrazine; Metolachlor; Leaching; Profiles; Models
68 NAL Call. No.: S539.5.J68
Environmental and economic impacts of pesticide and irrigation
practices: EPIC-PST simulation.
Sabbagh, G.J.; Norris, P.E.; Geleta, S.; Bernado, D.J.;
Elliott, R.L.; Mapp, H.P.; Stone, J.F.
Madison, Wis. : American Society of Agronomy; 1992 Jul.
Journal of production agriculture v. 5 (3): p. 312-317; 1992
Jul. Includes references.
Language: English
Descriptors: Oklahoma; Groundwater pollution; Crop management;
Environmental impact; Economic impact; Pest control;
Irrigation; Computer techniques; Simulation models;
Pesticides; Movement in soil; Runoff
69 NAL Call. No.: 292.8 W295
Estimating changes in recreational fishing participation from
national water quality policies.
Ribaudo, M.O.; Piper, S.L.
Washington, D.C. : American Geophysical Union; 1991 Jul.
Water resources research v. 27 (7): p. 1757-1763; 1991 Jul.
Includes references.
Language: English
Descriptors: Water quality; Water policy; Water pollution;
Angling; Participation; Estimation; Models
Abstract: The complete evaluation of the offsite effects of
national policies or programs that affect levels of
agricultural nonpoint source pollution requires linking
extensive water quality changes to changes in recreational
activity. A sequential decision model is specified to describe
an individual's decisions about fishing. A participation model
for recreational fishing that includes a water quality index
reflecting regional water quality is developed and estimated
as a logit model with national level data. A visitation model
for those who decide to fish that also includes the water
quality index is estimated using ordinary least squares. The
water quality index is found to be significant in the
participation model but not in the visitation model. Together,
the two models provide a means of estimating how changes in
water quality might influence the number of recreation days
devoted to fishing. The model is used to estimate changes in
fishing participation for the Conservation Reserve Program.
70 NAL Call. No.: TC401.W27
Estimating low flow characteristics in ungauged catchments.
Nathan, R.J.; McMahon, T.A.
Dordrecht : Kluwer Academic Publishers; 1992.
Water resources management v. 6 (2): p. 85-100; 1992.
Includes references.
Language: English
Descriptors: New South Wales; Victoria; Watersheds; Rural
areas; Flow; Characteristics; Water yield; Rain; Runoff;
Models; Multivariate analysis; Climatic factors; Hydrological
data; Equations
71 NAL Call. No.: 292.8 J82
Estimating transport parameters at the grid scale: on the
value of a single measurement.
Beven, K.J.
Amsterdam : Elsevier Scientific Publishers, B.V.; 1993 Mar01.
Journal of hydrology v. 143 (1/2): p. 109-123; 1993 Mar01.
Special Issue: Modelling Flow and Transport in the Unsaturated
Zone: Scale Problems and Spatial Variability. Includes
references.
Language: English
Descriptors: Solutes; Transport processes; Soil water; Flow;
Spatial variation; Hydrodynamic dispersion; Prediction;
Estimation; Probabilistic models
Abstract: Distributed models of solute transport at the field
and catchment scales require the specification of effective
parameters at the model grid scale. The grid scale will
generally be much larger than the scale at which it is
possible to make measurements to derive parameter values but
may be of the same order as the scale of variability of such
'point' values. In addition, measurements are usually
expensive and time consuming to make and where, for example,
'undisturbed' soil cores are used, may be destructive. This
paper describes a conditional probability based approach for
estimating grid scale effective parameter values in the light
of expected spatial heterogeneity, given only one or a small
number of available measurements. Initial results show,
somewhat surprisingly, that despite the integrative nature of
the spatial averaging involved in moving to the grid scale,
the variance of the effective grid element values does not
decrease. There is a small shift in the location of the
distribution, as a result of the macrodispersive effect of the
grid scale variability.
72 NAL Call. No.: GB746.W33
Estimation of possible anthropogenic changes in the runoff and
removal of biogenic elements from small watersheds of the
forest zone on the basis of a mathematical model.
Kondrat'ev, S.A.
New York, N.Y. : Consultants Bureau; 1991 Mar.
Water resources v. 17 (3): p. 240-248; 1991 Mar. Tranlated
from: Vodnye Resursy, V. 17, No. 3, May/June 1990, p. 24-32.
(GB746.V55). Includes references.
Language: English; Russian
Descriptors: U.S.S.R.in europe; Rsfsr; Runoff water; Sediment;
Formation; Water pollution; Nutrients; Removal; Phosphorus;
Nitrogen; Agricultural production; Effects; Watersheds;
Forests; Hydrology; Mathematical models
73 NAL Call. No.: 292.8 J82
Evaluating the green and ampt infiltration parameter values
for tilled and crusted soils.
Mohamoud, Y.M.
Amsterdam : Elsevier Scientific Publishers, B.V.; 1991 Feb.
Journal of hydrology v. 123 (1/2): p. 25-38; 1991 Feb.
Includes references.
Language: English
Descriptors: Illinois; Agricultural soils; Rain; Infiltration;
Soil water content; Runoff; Surface layers; Tillage; Crop
residues; Crusts; Permeability; Capillary rise; Wetting front;
Hydraulic conductivity; Mathematical models; Green and ampt
equation
Abstract: Methods for determining Green-Ampt infiltration
parameter values for tilled and crusted soils are not well
established. A two-stage method is developed to determine the
Green and Ampt parameter values for soils under different
management practices. The first stage is aimed at calculating
rainfall infiltration from rainfall and runoff data of small
field plots which had different soil surface conditions (e.g.
tillage, residue cover and crusting). To determine accurate
rainfall infiltration rates from field plots, we employed a
water balance model which accounted for depression storage,
detention storage as well as surface routing of runoff. The
second stage is aimed at evaluating the values of the Green
and Ampt infiltration equation parameters by the linear least
squares parameter estimation technique. The Green and Ampt
parameter values determined were the effective capillary
suction at the wetting front and the effective hydraulic
conductivity. The results of this study indicated that this
procedure is sufficiently sensitive to reflect the effects of
tillage, residue cover and crusting on infiltration data.
Raindrop impact reduced infiltration rates by crusting the
soil surface. However, most of the management systems that
left about 30% of residue cover protected the soil from
raindrop impact as evidenced by the higher effective hydraulic
conductivity. It is concluded that the model developed by
Green and Ampt in 1911 satisfactorily fitted the infiltration
data obtained from protected and crusted soil profiles. Also,
residue cover and crusting greatly influenced the Green and
Ampt infiltration parameter values.
74 NAL Call. No.: TP995.A1I5
Evaluating transport of organic chemicals in soil resulting
from underground fuel tank leaks.
Lee, D.Y.; Chang, A.C.
Chelsen, Mich. : Lewis Publishers; 1992.
Proceedings of the Industrial Waste Conference (46): p.
131-140; 1992. Meeting held May 14-16, 1991, West Lafayette,
Indiana. Includes references.
Language: English
Descriptors: Polluted soils; Soil pollution; Organic
compounds; Petroleum; Petroleum hydrocarbons; Transport
processes; Fuel tanks; Leakage; Underground storage;
Simulation models; Equations; Mathematics; Groundwater
pollution; Soil water movement; Movement in soil
75 NAL Call. No.: GB701.W375 no.91-4142
Evaluation of a ground-water flow and transport model of the
upper Coachella Valley, California.. Evaluation of a ground
water flow and transport model of the upper Coachella Valley,
California
Reichard, Eric George; Meadows, J. Kevin
Geological Survey (U.S.),California Regional Water Quality
Control Board--Colorado River Basin Region
Sacramento, Calif. : U.S. Geological Survey ; Denver, CO :
Books and Open-File Reports Section [distributor],; 1992.
vi, 101 p. : ill., maps ; 28 cm. (Water-resources
investigations report ; 91-4142). Includes bibliographical
references (p. 42).
Language: English
Descriptors: Groundwater flow; Water, Underground
76 NAL Call. No.: TD426.J68
Evaluation of a pesticide mobility index: impact of recharge
variation and soil profile heterogeneity.
Kleveno, J.J.; Loague, K.; Green, R.E.
Amsterdam : Elsevier; 1992 Oct.
Journal of contaminant hydrology v. 11 (1/2): p. 83-99; 1992
Oct. Includes references.
Language: English
Descriptors: Hawaii; Soil pollution; Pesticides; Profiles;
Movement in soil; Attenuation; Leaching; Assessment;
Simulation models; Errors; Movement to roots; Rain
77 NAL Call. No.: 290.9 AM32T
Evaluation of fluvial sediment transport equations for
overland flow. Guy, B.T.; Dickinson, W.T.; Rudra, R.P.
St. Joseph, Mich. : American Society of Agricultural
Engineers; 1992 Mar. Transactions of the ASAE v. 35 (2): p.
545-555. ill; 1992 Mar. Includes references.
Language: English
Descriptors: Geological sedimentation; Overland flow; Rain;
Runoff; Splash erosion; Simulation models
Abstract: Sediment transport capacity was measured under a
range of conditions in two types of overland flow: shallow
uniform flow in the absence of rainfall, and shallow flow
affected by rainfall impact. The abilities of six fluvial
sediment transport equations to represent each dataset are
evaluated. For both flow types, common aspects of equation
performance include poor representation of sediment transport
thresholds, underprediction of transport rates, and
significant scatter about measured values. These problems,
particularly the equations' inability to predict transport
threshold, are more evident with the rain-impacted now data.
Only the Schoklitsch equation is suitable for uniform overland
flow without rain-impact, and none am suitable for rain-
impacted overland flow.
78 NAL Call. No.: 290.9 AM32T
Evaluation of PRZM and LEACHMP on intact soil columns.
Smith, W.N.; Prasher, S.O.; Barrington, S.F.
St. Joseph, Mich. : American Society of Agricultural
Engineers; 1991 Nov. Transactions of the ASAE v. 34 (6): p.
2413-2420; 1991 Nov. Includes references.
Language: English
Descriptors: Atrazine; Computer simulation; Leaching; Soil
properties; Water pollution
Abstract: Limiting factors towards the utilization of
pesticide transport models are lack of both detailed data and
cognizant personnel available to test and validate model
predictions. In this study, computer simulations were carried
out to test the performance of PRZM (a management model) and
LEACHMP (a research model) on leaching characteristics of
atrazine in long intact soil columns. Also, in an attempt to
evaluate model uncertainty, a sensitivity analysis of several
parameters for each model was considered. LEACHMP was found to
be superior in predicting hydrological characteristics in the
soil columns as compared to PRZM which required calibration.
Both models underestimated levels of atrazine near the soil
surface and in the leachate (115 cm depth) and over-estimated
them throughout most of the range in-between. Inaccurate
predictions for the two models are attributed to simplistic
linear adsorption equations and lack of a macropore flow
subroutine. In increasing order, PRZM was most sensitive to
rate of application, distribution coefficient, bulk density
and field capacity, whereas LEACHMP was sensitive to rate of
application, organic carbon distribution coefficient, air
entry value, and bulk density.
79 NAL Call. No.: 292.8 J82
Evaluation of the accuracy and precision of annual phosphorus
load estimates from two agricultural basins in Finland.
Rekolainen, S.; Posch, M.; Kamari, J.; Ekholm, P.
Amsterdam : Elsevier Scientific Publishers, B.V.; 1991 Nov.
Journal of hydrology v. 128 (1/4): p. 237-255; 1991 Nov.
Includes references.
Language: English
Descriptors: Finland; Agricultural land; Drainage; Runoff;
Pollution; Phosphorus; Transport processes; Flow; Estimates;
Sampling; Frequency; Monitoring; Mathematical models;
Comparisons
Abstract: The accuracy and precision of phosphorus load
estimates from two agricultural drainage basins in western
Finland were evaluated, based on continuous flow measurements
and frequent flow-proportional sampling of total phosphorus
concentration during a 2 year period. The objective was to
compare different load calculation methods and to evaluate
alternative sampling strategies. An hourly data set of
concentrations was constructed by linear interpolation, and
these data were used in Monte Carlo runs for producing
replicate data sets for calculating the accuracy and precision
of load estimates. All estimates were compared with reference
values computed from the complete hourly data sets. The load
calculation methods based on summing the products of regularly
sampled flows and concentrations produced the best precision,
whereas the best accuracy was achieved using methods based on
multiplying annual flow by flow-weighted annual mean
concentration. When comparing different sampling strategies,
concentrating sampling in high runoff periods (spring and
autumn) was found to give better accuracy and precision than
strategies based on regular interval sampling throughout the
year. However, the best result was obtained by taking samples
flow-proportionally within the highest peak flows plus
additional regular interval (e.g. biweekly) samples outside
these flow peaks. Using this strategy, which calls for
automatic sampling equipment, accuracies better than 5% and
precisions better than 10% can be achieved with only 30-50
samples per year.
80 NAL Call. No.: 290.9 AM32T
Evaluation of the hydrologic component of the ADAPT water
table management model.
Chung, S.O.; Ward, A.D.; Schalk, C.W.
St. Joseph, Mich. : American Society of Agricultural
Engineers; 1992 Mar. Transactions of the ASAE v. 35 (2): p.
571-579; 1992 Mar. Includes references.
Language: English
Descriptors: Tile drainage; Water management; Water table;
Evapotranspiration; Hydrology; Macropore flow; Runoff;
Seepage; Simulation models
Abstract: A subsurface, water table management model ADAPT
(Agricultural Drainage and Pesticide Transport) has been
developed by combining drainage and subirrigation algorithms
from DRAINMOD with the GLEAMS model. In addition, the model
incorporates improved snow melt and runoff algorithms,
macropore flow due to cracking, and deep seepage. Theory for
the hydrologic components of the model is presented together
with an evaluation of the model using data from a long-term
field experiment at Castalia in North Central Ohio. Predicted
surface runoff, subsurface drainage, and combined surface and
subsurface drainage are compared with the field observations.
In general, the model predictions are within the range of the
variations of the observed replications. Sensitivity analysis
shows that surface runoff estimates are sensitive to changes
in curve number, while subsurface drainage flows are sensitive
to deep seepage estimates. Model input requirements are not
excessive and the model gives reasonable estimates of the
hydrologic component of water table management systems. ADAPT
can be used in designing water table management systems and
does not require extensive calibration. The pesticide
component of ADAPT is currently being evaluated and
development of a nutrient component has been initiated.
81 NAL Call. No.: 4 AM34P
Evaluation of the nitrogen submodel of CERES-maize following
legume green manure incorporation.
Bowen, W.T.; Jones, J.W.; Carsky, R.J.; Quintana, J.O.
Madison, Wis. : American Society of Agronomy; 1993 Jan.
Agronomy journal v. 85 (1): p. 153-159; 1993 Jan. Includes
references.
Language: English
Descriptors: Simulation models; Prediction; Nutrient uptake;
Nitrogen; Green manures; Nutrient availability;
Mineralization; Leaching; Nitrate; Losses from soil; Nitrogen
balance
Abstract: Crop simulation models that accurately predict the
availability of N from decomposing plant residues would
provide a powerful tool for evaluating legume green manures as
potential N sources for nonlegume crops. Using measured data
from a series of field experiments conducted on an Oxisol in
central Brazil, we conducted this study to test the N submodel
of CERES-Maize for its ability to simulate N mineralization,
nitrate leaching, and N uptake by maize (Zea Mays L.)
following the incorporation of 10 different legume green
manures. Legume or weed residue N at the time of incorporation
varied from 25 to 300 kg ha-1 with C/N ratios varying from 13
to 37. Comparison of predicted and measured accumulation of
inorganic N in uncropped soil showed that the model usually
provided a realistic simulation of legume N release, although
N release was overpredicted for some legumes. For all legumes,
both simulated and measured data showed that about 60% of the
organic N applied was recovered as inorganic N within 120 to
150 d after incorporation. To realistically simulate N
availability when rainfall was excessive, we modified the
model to account for delayed leaching due to nitrate retention
in the subsoil. Nitrogen uptake by maize was generally
overpredicted at high levels of available N. The N submodel
was shown to realistically simulate legume N release, but
further work is needed to determine the importance of subsoil
nitrate retention in other soils and how best such retention
might be described in the model.
82 NAL Call. No.: 290.9 AM32T
An evaluation of unit stream power theory for estimating soil
detachment and sediment discharge from tilled soils.
McIsaac, G.F.; Mitchell, J.K.; Hummel, J.W.; Elliot, W.J. St.
Joseph, Mich. : American Society of Agricultural Engineers;
1992 Mar. Transactions of the ASAE v. 35 (2): p. 535-544; 1992
Mar. Includes references.
Language: English
Descriptors: Illinois; Water erosion; Aggregates; Runoff;
Sediment yield; Simulation models; Soil properties; Streams;
Tillage
Abstract: Unit Stream Power (USP) and the associated Yang
(1973) sediment transport equations were compared to soil
detachment rates and sediment concentrations in runoff from
eroding soils. Although USP was significantly correlated with
rill detachment rates, potential energy dissipation rate per
unit rill area was a better predictor of soil detachment
rates. The Yang (1973) equations estimated sediment
concentrations within a factor of 10 of the observed
concentrations, if the median soil aggregate diameter was
within the range of diameters used by Yang to estimate the
equation parameters. When median aggregate sizes were less
than 0.15 mm, the lower limit of Yang's (1973) calibration
range, the equations tended to produce unrealistically large
estimates of sediment concentration.
83 NAL Call. No.: ViBlbVLD5655.V856 1992.J663
Evaluation of water distribution system monitoring using
stochastic dynamic modeling.
Jones, Philip Edward James,
1992; 1992.
xiv, 215 leaves : ill. ; 28 cm. Vita. Abstract.
Bibliography: leaves 181-191.
Language: English
Descriptors: Water quality management; Water
84 NAL Call. No.: 56.8 SO3
Exit condition for miscible displacement experiments.
Parlange, J.Y.; Starr, J.L.; Van Genuchten, M.Th; Barry, D.A.;
Parker, J.C. Baltimore, Md. : Williams & Wilkins; 1992 Mar.
Soil science v. 153 (3): p. 165-171; 1992 Mar. Includes
references.
Language: English
Descriptors: Transport processes; Solutes; Soil solution; Soil
analysis; Mathematical models; Determination; Convection;
Dispersion; Length; Movement in soil; Kinetics
85 NAL Call. No.: 56.8 SO3
Experimental and simulated B transport in soil using a
multireaction model. Mansell, R.S.; Bloom, S.A.; Burgoa, B.;
Nkedi-Kizza, P.; Chen, J.S. Baltimore, Md. : Williams &
Wilkins; 1992 Mar.
Soil science v. 153 (3): p. 185-194; 1992 Mar. Includes
references.
Language: English
Descriptors: Florida; Spodosols; Acid soils; Sandy soils; B
horizons; Subsurface layers; Phosphorus; Movement in soil;
Transport processes; Soil water movement; Determination;
Laboratory methods; Simulation models; Mathematical models;
Sorption; Kinetics; Sorption isotherms; Comparisons; Fixation;
Soil organic matter; Aluminum oxide; Iron oxides
86 NAL Call. No.: HC79.E5E5
Exploring the effects of multiple management objectives and
exotic species on Great Lakes food webs and contaminant
dynamics.
Fontaine, T.D.; Stewart, D.J.
New York, N.Y. : Springer-Verlag; 1992 Mar.
Environmental management v. 16 (2): p. 225-229; 1992 Mar.
Includes references.
Language: English
Descriptors: Fishery management; Lakes; Water quality; Food
chains; Objectives; Simulation models
87 NAL Call. No.: S539.5.J68
Farm-level economic and environmental impacts of eastern Corn
Belt cropping systems.
Foltz, J.C.; Lee, J.G.; Martin, M.A.
Madison, WI : American Society of Agronomy, c1987-; 1993 Apr.
Journal of production agriculture v. 6 (2): p. 290-296; 1993
Apr. Includes references.
Language: English
Descriptors: Corn belt states of U.S.A.; Cabt; Zea mays;
Medicago sativa; Glycine max; Microeconomic analysis; Economic
impact; Alternative farming; Environmental impact; Rotations;
Continuous cropping; Simulation models; Computer simulation;
Erosion; Runoff; Pesticides; Water pollution
88 NAL Call. No.: TD201.A4 A
fast and accurate method for solving subsurface contaminant
transport problems with a single uncertain parameter.
Ahlfeld, D.P.; Pinder, G.F.
Essex : Elsevier Science Publishers Ltd; 1992.
Advances in water resources v. 15 (2): p. 143-150; 1992.
Includes references.
Language: English
Descriptors: Groundwater pollution; Contaminants; Transport;
Equations; Random sampling; Stochastic models; Groundwater
flow; Hydraulic conductivity
89 NAL Call. No.: QH545.A1E58
Fate, dissipation and environmental effects of pesticides in
southern forests: a review of a decade of research progress.
Neary, D.G.; Bush, P.B.; Michael, J.L.
Tarrytown, N.Y. : Pergamon Press; 1993 Mar.
Environmental toxicology and chemistry v. 12 (3): p. 411-428;
1993 Mar. Paper presented at the "Symposium on Pesticides in
Forest Management, 11th Annual Meeting of the Society of
Environmental Toxicology and Chemistry," November 11-15, 1990,
Arlington, Virginia. Literature review. Includes references.
Language: English
Descriptors: Southern states of U.S.A.; Pesticides; Forestry;
Ecosystems; Watersheds; Environmental impact; Water quality;
Air quality; Groundwater pollution; Silviculture; Species
diversity; Simulation models; Nontarget effects; Literature
reviews
90 NAL Call. No.: QH540.N3
Fate of non-aqueous phase liquids: modeling of surfactant
effects. Harwell, J.H.; Sabatini, D.A.; Soerens, T.S.
Berlin, W. Ger. : Springer-Verlag; 1993.
NATO ASI series : Series G : Ecological sciences v. 32: p.
309-328; 1993. In the series analytic: Migration and fate of
pollutants in soils and subsoils / edited by D. Petruzzelli
and F.G. Helfferich. Proceedings of the NATO Advanced Study
Institute, May 24-June 5, 1992, Maratea, Italy. Includes
references.
Language: English
Descriptors: Soil pollution; Groundwater pollution;
Pollutants; Organic compounds; Transport processes;
Groundwater flow; Soil water movement; Equations; Mathematics
91 NAL Call. No.: TP963.A1F4
Fertilization under drip irrigation.
Bar-Yosef, B.
New York, N.Y. : Marcel Dekker; 1991.
Fertilizer science and technology series v. 7: p. 285-329;
1991. In the series analytic: Fluid fertilizer science and
technology / edited by D.A. Palgrave. Includes references.
Language: English
Descriptors: Fertigation; Liquid fertilizers; Fluids; Trickle
irrigation; Fertilizer requirement determination; Irrigation
water; Ph; Salinity; Plant nutrition; Nutrient requirements;
Nutrient uptake; Temporal variation; Nitrogen; Movement in
soil; Transport processes; Spatial distribution; Root systems;
Soil water content; Soil solution; Mathematical models;
Monitoring; Fertilizer technology; Management; Crop production
92 NAL Call. No.: QD1.A45
Field and model estimates of pesticide runoff from turfgrass.
Rosenthal, W.D.; Hipp, B.W.
Washington, D.C. : The Society; 1993.
ACS Symposium series - American Chemical Society (522): p.
208-213; 1993. In the series analytic: Pesticides in urban
environments: Fate and significance / edited by K.D. Racke and
A.R. Leslie. Paper presented at the 203rd National Meeting of
the American Chemical Society, April 5-10, 1992, San
Francisco, California. Includes references.
Language: English
Descriptors: Chlorpyrifos; Carbaryl; Diazinon; 2,4-d; Dicamba;
Atrazine; Fertilizers; Herbicide residues; Insecticide
residues; Runoff water; Mathematical models; Simulation
models; Cynodon dactylon; Buchloe dactyloides
Abstract: Environmental awareness of surface runoff water
quality is increasing. A study was conducted to analyze the
impact of different turfgrass fertilizer and pesticide
management systems on runoff water quality. A hydrologic and
water quality model, Erosion Productivity Impact Calculator
(EPIC), was used to estimate pesticide and nutrient
concentrations in runoff from turfgrass on a Houston Black
Clay. Nutrient and pesticide concentrations in the surface
runoff increased significantly for highly maintained turfgrass
systems. A larger fraction of the amount applied was observed
in runoff for the moderate application rate treatments.
Simulated results are being validated from measured runoff of
turfgrass plots at Dallas, TX.
93 NAL Call. No.: S478.S68T43 no.31
Field measurement and modelling of runoff and erosion response
of small agricultural catchments in the mid north of South
Australia. Punthakey, J.F.
Adelaide, South Australia : Dept. of Agriculture,; 1992.
v, 137 p. : ill. ; 30 cm. (Technical paper (South Australia.
Dept. of Agriculture) ; no. 31.). May 1992. AGDEX 572.
Includes bibliographical references (p. 134-137) and index.
Language: English
94 NAL Call. No.: 56.9 SO3
Field study of bromacil transport under continuous-flood
irrigation. Jaynes, D.B.
Madison, Wis. : The Society; 1991 May.
Soil Science Society of America journal v. 55 (3): p. 658-664;
1991 May. Includes references.
Language: English
Descriptors: Bromacil; Flood irrigation; Herbicide residues;
Leaching; Movement in soil; Transport processes; Agricultural
soils; Mathematical models
Abstract: The transport processes of sorbing chemicals in
field soils are poorly understood. This study characterized
the leaching behavior of the weakly sorbing herbicide bromacil
(5-bromo-3-sec-butyl-6-methyluracil) in comparison to Br-
during continuous-flood irrigation of a small field plot.
Twenty-four solution samplers were used to periodically
collect in situ samples from seven depths within four 1.83 by
1.83 m subplots. Estimates of the pore water velocity (vs) and
dispersion coefficient (D) were made by fitting an analytical
solution of the convection-dispersion (CD) equation to the Br-
data. Estimates of retardation (R) were made by fitting the CD
equation to the bromacil data using the vs and D estimates
from the Br- data and letting R be a fitting parameter.
Estimates of R were also made from the results of batch
equilibration studies using soil from seven depths. Best-fit
vs and D values exhibited considerable variability from
sampler to sampler (CV = 1.25 and 1.30, respectively) and
showed no significant trends with depth. Retardation values
estimated from the CD equation averaged 1.88, but varied from
1.21 to 3.35 and also showed no significant trend with depth.
In contrast, batch equilibration studies showed the absorption
properties of the surface 0.6 m of soil to be significantly
different than the 0.6- to 3-m depth, with R values decreasing
from 1.62 for the surface 0.6 m to 1.31 at 3 m. Although the
two methods gave the same estimate of R in the surface soil
neither the lower R values at deeper depths nor the tendency
to decrease with depth as predicted from the batch studies was
apparent in the transport data. Using D as an additional
fitting parameter to the bromacil data resulted in an average
increase of 1.96 for this parameter, indicating more
dispersion for the sorbing solute. Increased dispersion and
increased tailing of the sorbed solute may be attributed to
spatially variable adsorption and to a negative correlation
between vs and R (r = -0.524)
95 NAL Call. No.: 290.9 AM32T
Field testing and comparison of the PRZM and GLEAMS models.
Smith, M.C.; Bottcher, A.B.; Campbell, K.L.; Thomas, D.L. St.
Joseph, Mich. : American Society of Agricultural Engineers;
1991 May. Transactions of the ASAE v. 34 (3): p. 838-847; 1991
May. Includes references.
Language: English
Descriptors: Georgia; Alachlor; Atrazine; Bromides; Field
tests; Leaching; Groundwater; Pesticides; Precipitation;
Runoff; Simulation models; Soil properties; Soil water
Abstract: The root/vadose zone transport models PRZM and
GLEAMS were tested against an experimental data set.
Parameters were not optimized or calibrated to produce the
best fit. In all cases the measured and predicted peak
concentrations agreed within an order of magnitude, and in
most cases agreed within a factor of 2 to 3. This level of
agreement between the models and the measured data is within
the criteria for model acceptance suggested by the EPA. The
small differences noted in simulated transport between the
models are thought to be a result of differences in
computational layering and chemical transport calculation
methods.
96 NAL Call. No.: TD426.J68
Fluid flow and solute transport processes in unsaturated
heterogeneous soils: Preliminary numerical experiments.
Liu, C.C.K.; Loague, K.; Feng, J.S.
Amsterdam : Elsevier; 1991 Feb.
Journal of contaminant hydrology v. 7 (3): p. 261-283; 1991
Feb. Includes references.
Language: English
Descriptors: Movement in soil; Pollutants; Unsaturated flow;
Mathematical models; Finite element analysis; Prediction;
Aquifers
97 NAL Call. No.: S539.5.J68
Functional form selection for regional crop response to
salinity, water application, and climate.
Lee, D.J.
Madison, Wis. : American Society of Agronomy; 1992 Oct.
Journal of production agriculture v. 5 (4): p. 445-454; 1992
Oct. Includes references.
Language: English
Descriptors: Zea mays; Sorghum bicolor; Triticum aestivum;
Triticum turgidum; Irrigation; Application rates; Saline
water; Water quality; Mathematical models; Crop yield; Soil
salinity; Climatic factors
98 NAL Call. No.: QH540.J6 A
functional model of solute transport that accounts for bypass.
Corwin, D.L.; Waggoner, B.L.; Rhoades, J.D.
Madison, Wis. : American Society of Agronomy; 1991 Jul.
Journal of environmental quality v. 20 (3): p. 647-658; 1991
Jul. Includes references.
Language: English
Descriptors: Groundwater; Water quality; Transport processes;
Solutes; Water management; Mathematical models
Abstract: Public awareness of groundwater contamination has
created renewed interest in solute transport models that can
be practically applied as groundwater quality management
tools. Because of their simplicity with regard to input
requirements, functional models of solute transport are
excellent groundwater quality management tools. A functional
model of one-dimensional solute transport that accounts for
hydraulic bypass is presented. The transport model TETrans,
simulates the vertical movement of nonvolatile solutes (i.e.,
trace elements and nonvolatile organic chemicals) through the
vadose zone. Plant water uptake is taken into account assuming
no solute uptake by the plant. TETrans requires minimal input
data for its operation. Since TETrans uses a mass-balance
approach to solute transport, it offers the speed of an
analytical solution and the versatility of a numerical
approach without the need for input parameters, which are
difficult to measure. TETrans is able to account for bypass
with a single term, the mobility coefficient. The mobility
coefficient, gamma, represents the fraction of the soil liquid
phase, which is subject to piston-type displacement;
therefore, 1 - gamma represents the fraction of the liquid
phase that is bypassed. The mobility coefficient is a
temporally and spatially variable parameter (within a range of
0 to l) which is calculated from the deviation of the measured
chloride concentration from the predicted concentration
assuming piston displacement and assuming complete mixing of
the resident soil solution and incoming water for a given
irrigation and volume of soil. A constant mobility coefficient
for a given depth or entire profile can be determined by
averaging temporally varying mobility coefficients or
averaging spatially and temporally varying mobility
coefficients, respectively. In essence, the mobility
coefficient simplistically accounts for three physical
transport phenomena in a single term. On a microscopic level
there is flow thr
99 NAL Call. No.: 290.9 AM32T
Generic anaerobic digestion model for the simulation of
various reactor types and substrates.
Thomas, M.V.; Nordstedt, R.A.
St. Joseph, Mich. : American Society of Agricultural
Engineers; 1993 Mar. Transactions of the ASAE v. 36 (2): p.
537-544; 1993 Mar. Literature review. Includes references.
Language: English
Descriptors: Florida; Agricultural wastes; Animal wastes;
Hyacinths; Manures; Straw; Waste disposal; Anaerobic
digestion; Literature reviews; Mathematical models; Methane
production
Abstract: A mathematical model was developed to represent a
wide variety of anaerobic reactor types and substrates. The
model is a generic, anaerobic digestion process model, using
lumped substrate parameters, and was developed for use as
type-specific reactor model operating within the sphere of a
larger system model. Three types of anaerobic reactors were
simulated: fixed-bed reactors, conventional stirred tank
reactors, and continuously expanding reactors. The generic
anaerobic digestion model provided a tool for testing various
values of conversion efficiency and kinetic parameters for a
wide range of substrate types and reactor designs.
100 NAL Call. No.: 292.8 W295 A
geochemical transport model for redox-controlled movement of
mineral fronts in groundwater flow systems: a case of nitrate
removal by oxidation of pyrite. Engesgaard, P.; Kipp, K.L.
Washington, D.C. : American Geophysical Union; 1992 Oct.
Water resources research v. 28 (10): p. 2829-2843; 1992 Oct.
Includes references.
Language: English
Descriptors: Denmark; Groundwater flow; Transport processes;
Denitrification; Pyrites; Oxidation; Nitrate; Reduction; Redox
reactions; Geochemistry; Spatial distribution; Algorithms;
Mathematical models; Simulation
Abstract: A one-dimensional prototype geochemical transport
model was developed in order to handle simultaneous
precipitation-dissolution and oxidation-reduction reactions
governed by chemical equilibria. Total aqueous component
concentrations are the primary dependent variables, and a
sequential iterative approach is used for the calculation. The
model was verified by analytical and numerical comparisons and
is able to simulate sharp mineral fronts. At a site in
Denmark, denitrification has been observed by oxidation of
pyrite. Simulation of nitrate movement at this site showed a
redox front movement rate of 0.58 m yr-1, which agreed with
calculations of others. It appears that the sequential
iterative approach is the most practical for extension to
multidimensional simulation and for handling large numbers of
components and reactions. However, slow convergence may limit
the size of redox systems that can be handled.
101 NAL Call. No.: 56.9 SO32
Geographic information system for differentiating unused
wells. Tan, Y.R.; Shih, S.F.
S.l. : The Society; 1991.
Proceedings - Soil and Crop Science Society of Florida v. 50:
p. 110-116; 1991. Paper presented at the "Symposium on
Reality of Sustainable Agriculture in Florida, September
26-28, 1990, Daytona Beach, FLorida. Includes references.
Language: English
Descriptors: Florida; Groundwater; Wells; Water management;
Geographical distribution
102 NAL Call. No.: QE1.E5
Geostatistical modeling of salinity as a basis for irrigation
management and crop selection--a case study in central
Tunisia.
Soderstrom, M.
New York, N.Y. : Springer; 1992 Sep.
Environmental geology and water sciences v. 20 (2): p. 85-92;
1992 Sep. Includes references.
Language: English
Descriptors: Tunisia; Groundwater; Saline water; Irrigation
water; Spatial distribution; Soil salinity; Irrigated soils;
Wells; Water; Soil; Sampling; Maps; Leaching; Models;
Irrigation scheduling; Crop yield; Yield losses; Crops;
Selection
103 NAL Call. No.: QH541.5.D4J6 A
GIS approach to desertification assessment and mapping.
Grunblatt, J.; Ottichilo, W.K.; Sinange, R.K.
London : Academic Press; 1992 Jul.
Journal of arid environments v. 23 (1): p. 81-102; 1992 Jul.
Includes references.
Language: English
Descriptors: Kenya; Desertification; Remote sensing; Satellite
imagery; Models; Geography
104 NAL Call. No.: S671.A66
GIS-assisted input data set development for the Finite Element
Storm Hydrograph Model (FESHM).
Wolfe, M.L.
St. Joseph, Mich. : American Society of Agricultural
Engineers; 1992 Mar. Applied engineering in agriculture v. 8
(2): p. 221-227; 1992 Mar. Includes references.
Language: English
Descriptors: Hydrology; Simulation models; Automation;
Computer techniques
Abstract: A study was conducted to develop an automated
proceedings to assist in the development of input data sets
for the FESHM hydrologic model using the GRASS geographic
information system. Shell scripts (executable sequences of
commands in the UNIX operating system) were developed to
overlay soils and land use maps to generate hydrologic
response unit (HRU) maps and to compute the fractional areas
of HRUs in overland flow elements. The automated procedures
decreased the input data set development time significantly,
by approximately 250% (from five to two hours) for a 122 ha
(303 ac) watershed. The time savings on larger, more variable
watersheds would be even greater. The input data set
development procedure provides an efficient manner for
considering alternative land use and management scenarios.
105 NAL Call. No.: 292.9 AM34
Ground water quality implications of soil conservation
measures: an economic perspective.
Setia, P.; Piper, S.
Bethesda, Md. : American Water Resources Association; 1991
Mar. Water resources bulletin v. 27 (2): p. 201-208; 1991 Mar.
Includes references.
Language: English
Descriptors: Corn belt of U.S.A.; Soil conservation;
Groundwater; Water quality; Pesticides; Runoff; Leaching;
Agricultural economics; Usda; Federal programs
Abstract: An evaluation of the intermedia movement of
pesticides applied under various land management systems
already in place, or to be implemented, under the Conservation
Reserve and Conservation Compliance programs is presented. The
simulation modeling approach followed in this analysis
consists of a mathematical programming model and
leaching/surface runoff, Pesticide Root Zone Model (PRZM)
models. Special care was taken to ensure that the physical
model was sensitive to the chemical characteristics of
individual pesticides and the important physical changes
brought about by different agricultural practices. Results
show that, although these programs as now planned, increase
farm income and achieve soil conservation goals, they may
adversely affect ground water quality. Also, depending on soil
and location characteristics, there are tradeoffs between
surface and ground water quality implications. Hence, if these
programs are to address water quality problems, the
recommended practices must be evaluated for their impact on
water quality, particularly in potentially vulnerable areas.
106 NAL Call. No.: QD1.A45
Groundwater and surface water risk assessments for proposed
golf courses. Cohen, S.Z.; Durborow, T.E.; Barnes, N.L.
Washington, D.C. : The Society; 1993.
ACS Symposium series - American Chemical Society (522): p.
214-227; 1993. In the series analytic: Pesticides in urban
environments: Fate and significance / edited by K.D. Racke and
A.R. Leslie. Paper presented at the 203rd National Meeting of
the American Chemical Society, April 5-10, 1992, San
Francisco, California. Includes references.
Language: English
Descriptors: Hawaii; Massachusetts; Golf courses; Golf green
soils; Herbicide residues; Insecticide residues; Leaching;
Leachates; Runoff; Surface water; Water pollution; Groundwater
pollution; Mathematical models; Simulation models; Risk;
Fungicides; Pesticide residues; Fertilizers; Nitrogen
Abstract: Proposed golf course developments usually require
environmental impact statements in the U.S. Concerns about
ground water, surface water, and near-shore coastal water
quality and wetlands often require state-of-the-art risk
assessments and complex computerized simulation modeling. It
is extremely important to obtain site-specific data for these
risk assessments. Thus soil sampling, test borings, stream
surveys, and coastal surveys are often done. Daily weather
records are obtained or generated. The new PRZM-VADOFT model
pair is used for leaching assessments, even though nonlinear
adsorption isotherms cannot be used. The SWRRBWQ model is
difficult to use but it is appropriate for the modeling of
complex drainage patterns at the basin and sub-basin scale, as
with golf courses. Annual and storm-event runoff values are
computed for pesticides, nutrients, runoff water, and
sediments. It is best used for areas expected to experience
appreciable runoff. EXAMS II provides useful predictions of
stream water quality. An uncertainty analysis is a critical
but often overlooked part of modeling. These results help fine
tune proposed turf management programs and may indicate the
need for design changes. Risk assessments in Hawaii are
especially complex; they often indicate the need for detention
basins.
107 NAL Call. No.: TD420.A1E5
Herbicide transport in rivers: importance of hydrology and
geochemistry in nonpoint-source contamination.
Squillace, P.J.; Thurman, E.M.
Washington, D.C. : American Chemical Society; 1992 Mar.
Environmental science & technology v. 26 (3): p. 538-545; 1992
Mar. Includes references.
Language: English
Descriptors: Iowa; Minnesota; Herbicide residues; Water
pollution; River water; Groundwater pollution; Concentration;
Models; Overland flow
108 NAL Call. No.: S601.A34
High bed-low ditch system in the Pearl River Delta, South
China. Ming, L.S.; Jian, L.R.
Amsterdam : Elsevier; 1991 Jun14.
Agriculture, ecosystems and environment v. 36 (1/2): p.
101-109; 1991 Jun14. Includes references.
Language: English
Descriptors: China; Delta soils; Alluvial soils; Deltas;
Subtropics; Saccharum officinarum; Musa paradisiaca; Citrus
reticulata; Oryza sativa; Sustainability; Ditches; High water
tables; Soil depth; Roots; Growth; Erosion; Sediment;
Nutrients; Losses from soil systems; Cycling; Flow; Models;
Crop production; Agricultural byproducts; Irrigation water;
Rain; Runoff water; Drainage water; Fertilizers; Dry matter
accumulation; Decomposition; Crop residues; Nitrogen;
Phosphorus pentoxide; Potassium; Nutrient content; Temporal
variation; Dry season; Rainy season; Water quality; Organic
matter
109 NAL Call. No.: TC163.I54 1992
Hydraulic and environmental modelling--estuarine and river
waters proceedings of the Second International Conference on
Hydraulic and Environmental Mod