Source Water Protection Activity Guide

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Use any of the following drop-down menus to navigate through the guide. Choosing a potential contaminant source category from the drop-down menu will narrow your potential contaminant source choices. Choosing a protection activity category from the drop-down menu will narrow your protection activity choices.

Contaminant Type

Potential Contaminant Source Category Potential Contaminant Source

Protection Activity Category Protection Activity

Irrigation Water Management

Protection Activity: Best Management Practices

Irrigation water management (IWM) involves a combination of management strategies aimed at delivering irrigation water in amounts and at times that best match crop water needs. Proper IWM can reduce the movement of pollutants such as salts, pesticides, nutrients, bacteria, and sediment from the land into ground or surface water sources. IWM strategies can include leveling irrigation land, efficiently applying irrigation water, scheduling irrigation, using runoff or tailwater, and managing drainage water.

Irrigation Land Leveling
Irrigation land leveling involves strategically reshaping the irrigated land surface to allow for uniform and efficient application of irrigation water and reduced runoff.

Irrigation Application Methods
Irrigation water can be applied using four basic methods: (1) surface (or flood), (2) sprinkler, (3) trickle, and (4) subsurface. When selecting the appropriate irrigation method, consider land slope, water intake rate of the soil, crop water needs, and wind. 

Irrigation Scheduling
Irrigation scheduling uses water management strategies to balance the water needs of a crop, avoiding both over- and under-application of water. Irrigation scheduling ensures the proper amount of water is applied to the crop when needed. 

Proper Tailwater Management
Tailwater management reduces the discharge of pollutants from surface runoff. Tailwater management systems that collect and/or store runoff and return it to the same or other fields for irrigation use include recovery and reuse facilities, return-flow or pumpback facilities, sequence-use facilities, reservoir systems, or cycling-sump facilities. 

Proper Drainage Water Management
Drainage management or water table control is an essential element of irrigation water management in places where the water table impinges upon the root zone. Drainage management practices are intended to control and manage soil moisture in the crop root zone, improve soil conditions, and improve plant root development. These practices can also benefit source water and crops by encouraging infiltration, reducing soil erosion, keeping salts leached below the root zone, and deepening the root zone. However, subsurface drainage systems can also have adverse impacts on water quality, so appropriate management practices—including water table management, treatment of drainage water, and reuse of drainage water—should be used to limit such impacts. If interested in these practices, seek assistance from an entity familiar with designing and operating drainage systems.

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