ROTO?A Continuous Water and Sediment Routing Model
A model called ROTO was developed to estimate water and sediment yields on large basins (several thousand square miles). ROTO is a continuous model operating on a daily time step that...
Neutron Physics Considerations in Moisture Probe Design
Neutron physics can be used to characterize most of the know behavior of neutrons in the soil. Scattering, absorption and slowing down are the principal processes affecting moisture probe...
Factors Affecting Neutron Gauge Calibration
Neutron gauge characteristics and soil chemistry affect gauge calibration. External factors also influence gauge calibration and should be considered in the calibration procedure. Gauge...
Access Tube Characteristics and Neutron Meter Calibration
Neutron meter calibration was found to be influenced by material type, thickness and size of access tube. Meter counts were decreased by an average of 15% for a 20% increase in tube diameter...
Relationship of Soil Type and Chemicals to the Calibration of Neutron Meters
Theory of neutron scattering and moderation in matter explains many of the characteristics of calibration curves of neutron moisture probes. Characteristics include effect of atomic species...
Sprinkler System Design for Frost Protection
Both undertree and overtree systems for frost protection by sprinkling are currently being used. The criteria based on experimental results and theoretical modeling have been reviewed...
Infiltration or Roughness from Surface Irrigation Advance
Over the past several decades, a significant effort has gone into the development of mathematical models of water flow over the soil surface. Significant progress has been made in prediction...
Upgrading of the Orange Cove Irrigation District Water Distribution System
The Orange Cove Irrigation District covers about 28,000 Acres in the Central Valley of California. It is supplied from the Friant-Kern Canal. A semi-closed low pressure pipeline system...
Conjunctive Use of Surface and Groundwater
A computer model was developed by T. Sammis and Z. Samani to simulate the conjunctive use of surface and groundwater. The model consisted of a groundwater simulation subroutine and a crop...
Using Neutron Probes to Aid Irrigation Scheduling
Neutron soil moisture measurements are used to supplement irrigation forecasts on the 60,000 acre sprinkler-irrigated Navajo Indian Irrigation Project (NIIP). Weekly irrigation forecasts...
Performance Measures for Irrigation Water Delivery
Performance measures are developed which facilitate analysis of irrigation water delivery systems in light of the objectives of adequacy, efficiency, dependability and equity and of water...
Measurement of Irrigation Water Use: Results of Two Case Studies in Illinois
Three methods of measuring and estimating irrigation pumpage were used during two research studies attempting to assess ground-water use. These three methods: (1) farmer estimates; (2)...
An Assessment of Input Variables to the Penman-Monteith Equation Using Canopy Reflectance Measurements
Observing the form of the Penman-J.L. Monteith equation, it can be seen that several terms could be potentially estimated from remotely sensed data. These include: net radiation, canopy...
Canal Automation for Flexibility on Sloping Canals
This project and tested a method which would allow flexible water deliveries from medium-large canals. The canal gate movement algorithm CARDD (Canal Automation for Rapid Demand Deliveries)...
Clean vs. Dirty Water Effects in Irrigation Systems
Seepage losses in irrigation systems may be significantly affected by the suspended solids concentrations of the water. Low-solids clean water increases losses; high-solids dirty water...
Research Needs in Movement of Agricultural Chemicals to Groundwater
Better prediction of the movement of agricultural chemicals to groundwater is necessary to permit development of best management practices to reduce adverse environmental effects of agriculture....
Stream Standards for Toxics and Irrigated Agriculture Using New Mexico as a Case Study
New Mexico follows a policy of 'antidegradation' with respect to the existing quality of a stream, but its standards specifically exclude return flows from irrigated...
Management Practice Effects on Water Quality
An array of resource conservation and water quality issues are providing research challenges and opportunities in soil and water, irrigation, and drainage. The key to addressing these...
Field Calibration of Neutron Gauges: SCS Method
Field calibration of neutron gauges is easy and requires very little time under normal circumstances. Special soil sampling equipment is required that can be fabricated by most machine...
Comparison of ET Measured with Neutron Moisture Meters and Weighing Lysimeters
The neutron moisture meter (N.M.) method of determining crop water use is frequently used in research and irrigated agriculture. This study was conducted to compare crop evapotranspiration...
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