Irrigation flow returns

Irrigation return flows. When farmers irrigate agricultural land, water not absorbed into the ground can flow into reservoirs for reuse. This return flow often picks up pesticide or fertilizer constituents, potentially rendering it hazardous. Because this water may be reused on the fields, it is excluded from the definition of solid waste. 

Causape J, Quilez D, Aragues R (2004) Assessment of irrigation and environmental quality at the hydrological basin level - II. Salt and nitrate loads in irrigation return flows. Agric Water Manage 70 211-228... 

Agriculture activities are one of the major generators of salinity but also one of the first to suffer its damage. The salinity of agricultural return flow is derived from two principal sources salinity of the irrigation water and the effects of added... 

Shaffer et al. (1977) Dutt et al. (1972) model extended to tile-drained croplands and incorporated into a large irrigation return flow model to handle nitrogen as well as dissolved mineral constituents. Model allows user to select the degree of sophistication in simulation or to bypass certain subroutines. Zero-order denitrification and transition-state nitrification added. Model verified for salinity but not nitrogen. 

Shaffer, M. J., Ribbens, R. W., and Huntly, C. W. (1977). Production of Mineral Quality of Irrigation Return Flow. V. Detailed Return Flow Salinity and Nutrient Simulation Model, EPA-600/2-77-179E. U.S. Environ. Prot. Agency, Ada. Oklahoma. 

The presence of parathion in the pond water and pond bottom muds was attributed to insecticide-laden soil washed in during a period of accelerated erosion. One-hundredth /xgram per liter of parathion, 0.02 /xgram per liter of DDD, and 0.01 /xgram per liter of BHC were found in the pond water 4 months after the last application of insecticides. Dunstan, Proctor, and Hindin (2) reported the presence of DDT, aldrin, and the isopropyl ester of 2, 4-D in a number of irrigation return flow wasteways in the Columbia Basin Project of Eastern Washington. 

In a classic paper, Pillsbury (1981) described how recycling of salts via irrigation and agricultural return flow controls the salinity of downstream rivers in arid zones. Once the natural salt balance is disturbed and salts begin to accumulate, either in the unsaturated zone or in drainage waters, the salinity increases. The salinity of the Colorado River is derived from a century of activity that includes upstream diversion of freshwater, massive irrigation, evapotranspiration and salt accumulation in the soil, and return of saline drainage back to the river (Pillsbury, 1981). Similarly, the rise of the salinity in the Nile Delta has been attributed to a disturbance of the natural salts balance after the construction of Assuan dam and the reduction of the natural outflow of salts from the Nile River to... 

Injection Wells Irrigation Return Flow Landfills Dry Land Farming... 

In contrast, effective eyewash streams are vertically oriented with a laminar flow. When eyewash streams are vertically oriented, they stall at a prescribed height providing a more comfortable eyewash experience. When the stream exhausts its vertical velocity, it softly turns outward and begins to fall off horizontally. This action causes a slight puddUng of the flow in midair before it returns to the eyewash bowl. It occurs directly at the optimal contact point with the eye, making for a more pleasant irrigation experience. 

RCRA excludes some substances. Examples are domestic sewage, irrigation return flow, point source discharge, certain mining waste, special nuclear, and other materials. Other laws cover them and other regulations control them. 

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