USDA NATURAL RESOURCES CONSERVATION SERVICE CONSERVATION PRACTICE STANDARD ARIZONA

PUMPED WELL DRAIN (no.)

CODE 532 DEFINITION needed to pump water from the aquifers are not included. A well sunk into an aquifer from which water is pumped to lower the prevailing water table. This standard does not apply to test wells established for investigating purposes before PURPOSES the installation of a permanent well because they are considered temporary. To provide subsurface drainage by lowering the prevailing water table to a level that will This practice applies to areas that have a high provide minimum benefits to crop or soils by water table and are in need of subsurface removing excess ground water and/or salts drainage, where pumping from wells is from the soil profile. feasible. This requires a permeable aquifer at a depth and of such thickness and magnitude CONDITIONS WHERE PRACTICE that, when pumped, will lower the water table APPLIES to the desired degree. This standard applies to drilled or driven wells An adequate outlet for the pumped drain water, used for pumping ground water to lower the considering its quantity and quality, must be water table level in a given area. It does not available. apply to vertical drains, sometimes called drainage wells, constructed to discharge drain effluent into porous underground formations. Pumps, motors, or other appurtenances NRCS Field Office Technical Guide, Section IV DRAFT NRCS-AZ Conservation practice standards are reviewed periodically, and updated if needed. To obtain May, 2002 the current version of this standard, contact the Natural Resources Conservation Service. 532-Pumped Well Drain

CRITERIA installation of the well, which will not adversely affect potable water sources and the Quantity of water. The amount of ground environment. water to be pumped from the well or wells shall be that required to provide the desired Cultural Resources drawdown in the area being drained. Multiple well drains. If more than one well is If this practice involves soil disturbance, the used in the system, the coned of depression area of potential effect for each undertaking developed by each shall overlap to such an must be investigated for cultural resources extent that the points of least drawdown will be under section 106 of the National Historical at the desired level after drainage. Preservation Act of 1966, as amended, before soil disturbance occurs. See the NRCS Depth and diameter. The well depth and Arizona Handbook of Cultural Resources diameter shall be of such that the amount of Procedures - Applicability and Exceptions water that can be drawn from the aquifer is Section - for identification of practices that are sufficient to maintain the desired drawdown exempt from, or that require cultural resources throughout the crop-growing season. Gravel surveys. envelopes may be used in conjunction with screens to serve as a filter and to increase the Endangered Species effective diameter of the well. Determine if installation of this practice with Casing. All wells shall be cased with steel, any others proposed practice will affect any concrete, plastic, asbestos-cement, or other federal, tribal, or state listed Threatened or material of adequate strength and durability. Endangered species or their habitat. NRCS's The casing shall have a diameter that is objective is to benefit these species or at least adequate to accommodate the required not have any adverse effect on a listed pumping equipment. species. If the Environmental Evaluation Screens. All wells shall be equipped with indicates the action may adversely affect a manufactured screen sections, well points, listed species or result in adverse modification shop-perforated metal casing sections, or field- of habitat of listed species which has been perforated sections meeting the criteria stated determined to be critical habitat, NRCS will below. advise the land user of the requirements of the Endangered Species Act and recommend The screen openings for aquifer material of alternative conservation treatments that avoid near uniform size shall be slightly smaller than the adverse effects. the average diameter of the aquifer material. For graded aquifer materials (of nonuniform Further assistance will be provided only if the gradation), the screen openings shall be of landowner selects one of the alternative such that 25 to 40 percent of the aquifer conservation treatments for installation; or at material is larger than the screen opening. the request of the landowners, NRCS may initiate consultation with the U.S. Fish and A sufficient length of screen shall be provided Wildlife Service. If the Environmental to maintain the entrance velocity of water into Evaluation indicates the action will not affect a the well at an acceptable level, preferably less listed species or result in adverse modification than 1/10 ft/s. of critical habitat, consultation generally will not apply and usually would not be initiated. The position of the screen in the well shall be Document any special considerations for governed by the depth of the aquifer below the endangered species in the Practice ground surface and the thickness of the aquifer Worksheet. to be penetrated by the well. Quality of water. If the water from the well CONSIDERATIONS drain is to be used for human consumption, it shall meet all requirements of the state health Water Quantity department or other state agencies having jurisdiction. If the water has a high salt content  Effects of the cone of depression on or is not potable, means of disposal shall be adjacent water uses and users. planned and installed concurrently with the  Downstream effects of the pumped water.

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Water Quality

 Effects of the quality of pumped water on the surrounding environment, water uses, or water users.  Effects of well pumping on soil and water salinity.  Effects of discharges of pumped water on downstream water temperatures.  Temporary and long-term effects on the visual quality of downstream waters.

PLANS AND SPECIFICATIONS Plans and specifications for constructing well drains shall be in keeping with this standard and shall describe the requirements for applying the practice to achieve its intended purpose.

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