The Use of Residence Time to Describe a Hillslope
Queueing theory has been applied to the determination of Soil Water Residence Time (SWRT) using an 18 year data set. The calculated SWRTs agree qualitatively with the lags exhibited by...
Nonpoint Source Pollution Model for Agricultural and Rural Watersheds
A dynamic hydrologic and nonpoint source pollution simulation model for agricultural and rural watersheds; capable of simulating rainfall-runoff, soil erosion, sediment transport, mixing...
Irrigation, Agrichemicals and the Environmental Impact, the Role of Hydrologic Non-Point Source Models
The importance of pollution loads from agricultural lands and the degradation of soils and water resources has brought about extensive efforts throughout the environmental and agricultural...
Dynamic Perspective on the Capillary Barrier Effect at the Interface of an Upper Fine Layer with a Lower Coarse Layer
The theoretical principles behind the determination of infiltration rate into a coarse layer overlain by a tight layer are reviewed. As a descending unsaturated wetting front hits the...
A Review of Fluid Movement in Compacted Clay: The Case of Macropore Flow
In constructing natural hydraulic barriers to infiltration, a typical design is one founded on the use of layers of compacted clay. Unfortunately, in analyzing the hydraulic performance...
Non-Intrusive Crack Detection in Clay Landfill Cover Liners
Laboratory and field studies were conducted to demonstrate that the azimuthal variation in electrical resistivity can be used to indicate the presence of cracks in clay systems. Laboratory...
Stormwater Infiltration Design Based on Rainfall Statistics and Soil Hydraulics
When comparing stormwater infiltration with other methods for stormwater drainage an appropriate design procedure is necessary. The method proposed for future Danish guidelines is based...
Estimating Detention Pond Efficiency by a Derived Distribution Approach
The paper describes a continuation effort by the first two writers in attempting to obtain a derived distribution for the outflow pollutant mass flexes from a wet detention pond. The derivation...
Application of Vadose Zone Flow and Transport Models
This paper summarizes application of two subsurface flow and transport models at Superfund sites, and evaluation of a number of other unsaturated zone models. The screening level models...
Modelling Studies of Gas Venting and Steam Injection for NAPL Site Remediation
A fully coupled, fully implicit method for simulating gas injection and steam injection for in situ remediation of sites contaminated with volatile NAPL is presented. Numerical results...
County Hydrology, Regional Approach
The effort to update the regional hydrology methods of the Santa Clara Valley Water District (District) entails a series of tasks that are long and difficult. This paper enumerates the...
Reactive Irrigation Scheduling for Sloping Furrow Irrigation
We developed a technique for estimating the proportion of the applied irrigation water that is effective when using furrow irrigation. To apply the method, irrigators would need to know...
Nitrogen and Phosphate in Vadose Waters in Heber Valley
During the last decade best management practices have been gradually implemented in Heber Valley to maintain and enhance the qualities of surface waters that flow into Deer Creek Reservoir....
Parameter Sensitivity of a Non-Linear, Process-Based Soil Erosion Model
Process-based, parameter distributed models have become widely accepted tools to predict the impacts of land use changes. Unfortunately these computer models are becoming more complex...
Sediment Entrapment by Stream Channel Vegetation
Degraded headwater streams are common in the mountainous West. They have experienced a variety of stresses from public and private uses and will require specific management consideration...
Primary Metals and Criteria for Water use in the Columbia River, British Columbia
We assessed primarily concentrations of lead, cadmium, copper, zinc and water hardness in the Columbia River between Birchbank and Waneta. Water quality in this reach of the river is affected...
Watershed Simulation for Characterizing Droughts Under the Influence of Climate Change
The paper describes a model for simulating soil moisture deficit on a daily basis using historical rainfall and climatic data for the analysis of droughts. Distributed parameter hydrologic...
Effect of Agricultural Drainage on Water Quality in the Great Lakes and Cornbelt States
The soils and the climate of the Great Lakes and Cornbelt states dictate that drainage is required to carry out economically viable farming activities. When drained, the soils are very...
Effects of Agricultural Drainage on Water Quality in the Lower Mississippi Valley and Gulf Coastal Region
Sediment and nutrient (N, P, K) losses were measured from research plots with surface drainage only and from plots with both surface and subsurface drainage for all or part of the decade,...
Models for Simulating Hydrology and Water Quality on Drained Soils
Design and operation of drainage and related water management systems should consider both agricultural production and environmental impacts. This is currently required in many locations...
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