Herbicides in Streams: Midwestern United States
Results from a 2-year study of 149 streams geographically distributed across the corn-producing region of 10 midwestern States show that detectable concentrations of herbicides persist...
Overall Resistance Parameter of Flow Arising in the Catchment-Area of a Reservoir in Steep Land
On a small reservoir catchment in mountains, the basin storage S(t) during a flood was expressed in terms of the basin discharge Q(t) and the time-varying storage parameters K(t) and P(t),...
Effects of Soil Layering on Infiltration
The effect of sloping soil layers on infiltration depends on the textural composition of both layers at the interface, as well as the slope of the interface. The contractions of flow caused...
Ground-Water Recharge from Streamflow Data, NW Florida
Annual base flows of streams draining Okaloosa County and adjacent areas in northwest Florida were determined through hydrograph separation and correlation techniques for purposes of evaluating...
The Effect of Channelization of R?o Puerto Nuevo on Ground-Water Levels in the San Juan Metropolitan Area, Puerto Rico
Channelization and concrete lining of the Rio Puerto Nuevo and its tributaries in the San Juan Metropolitan area has been proposed to control flooding in low lying areas adjacent to the...
Estimating Upland Recharge in the Yucca Mountain Area
Field and modeling studies were conducted recently for the Fortymile Canyon watershed and the Rock Valley area near the site of the proposed high-level nuclear waste repository at Yucca...
Flow Measurement in Irrigation Practice: State-of-the-Art
State-of-the-art flow metering developments for irrigation are reviewed. Selected older methods are updated with recent improvements. These include orifice meters, venturi meters, critical-flow...
An Analytical Technique of Flow Rate Into Perforated Draintubes
The flow rate into a draintube in a saturated soil media depends on numerous characteristics such as the hole size, the number and spacing of holes, the drain size and depth. Based on...
Effect of Choptank Watershed Drainage Project on Suspended Sediment Concentration
Between 1974 and 1982, the Soil Conservation Service, U.S.D.A. conducted a sediment concentration study on the Choptank Watershed in Caroline County, Maryland to monitor the effects of...
Canal Models and You
Unsteady canal simulation models require serious investments of time and personnel. The reasons for deciding to invest in a model, as well as reasons to not invest, are discussed. Canal...
Numerical Methods Used to Model Unsteady Canal Flow
Investigating the response characteristics of irrigation waer supply and distribution systems is essential if a good design is to be developed. Numerical simulation techniques have been...
Source of Atrazine and Desethylatrazine in a River, During Base Flow
A budget of atrazine and desethylatrazine loads was computed for a 116-kilometer reach of the Cedar River in Iowa to determine where these compounds enter the river during base-flow conditions....
Hydrologic and Geochemical Approaches for Determining Ground-Water Flow Components
Lyman Lake is an irrigation-storage reservoir on the Little Colorado River near St. Johns, Arizona. The main sources of water for the lake are streamflow in the Little Colorado River and...
Interaction of Irrigation Water and Drainage Flow
This study was conducted to evaluate the effect of irrigation management on subsurface drainage flow in an arid irrigated area. The irrigation management and drainage flow were monitored...
Unique Problems in Modeling Irrigation Canals
Irrigation-canal modeling is based on the same unsteady flow equations used for river modeling. However the canal and irrigation environment present several unique simulation problems...
Informed Use and Potential Pitfalls of Canal Models
Numerical models of unsteady flow in canals are used in the design, analysis and operation of irrigation canal systems. Their informed use requires knowledge of the potential pitfalls,...
Canal Model Evaluation and Comparison Criteria
The ASCE Task Committee on 'Irrigation Canal System Hydraulic Modeling' was formed to evaluate existing canal unsteady flow models (computer programs) and to...
A Coupled Surface-Water and Ground-Water Model
In areas with dynamic and hydraulically well connected ground-water and surface-water systems, it is desirable that stream-aquifer interaction be simulated with models of equal sophistication...
A New Method for Calculating a Mathematical Expression for Streamflow Recession
An empirical method has been devised to calculate the master recession curve, which is a mathematical expression for streamflow recession during times of negligible direct runoff. The...
Time Scales for Surface-Subsurface Flow Modeling
Traditionally, interactive free surface flow and subsurface flow are analyzed separately, using infiltration rate described by an infiltration formula as the common boundary condition....
Return to search