IDENTIFICATION AND EVALUATION OF POTENTIAL AQUIFER STORAGE AND RECOVERY SITES IN CACHE VALLEY, UTAH

Water managers in Cache County, Utah, are interested in implementing an aquifer storage and recovery project in Cache Valley, through either ponding water in surface basins where it can seep into the soil and infiltrate into the aquifer (surface spreading), or by injecting the water directly into the aquifer via a well (injection).

The principal basin-fill aquifer in Cache Valley consists of unconsolidated sediments 150-210 m thick. A confining clay layer above most of the principal aquifer limits potential surface-spreading sites to a narrow band along the eastern mountain front of Cache Valley. The distribution of the Salt Lake Formation, a less transmissive unit than the principal aquifer, further limits potential surface recharge sites to the area between Green Canyon, 3.5 km north of Logan, and Millville Canyon, 7.5 km south of Logan. We identified two potential surface-spreading sites within this target area, one near the mouth of Green Canyon in North Logan, and one east of Providence, 2 km south of Logan.

Because injection wells can penetrate clay layers to reach the aquifer, potential injection sites are limited only by the lateral extent of the principal aquifer. We identified an unused well near River Park Drive in the Island area of Logan that penetrates the principal aquifer as being suitable for use as an injection well.

We recommend pursuing injection using the River Park well rather than the surface-spreading sites. The principal advantages of the injection well are: (1) the sediments underlying the surface-spreading sites are uncertain and would require drilling exploration wells to verify the absence of the clay confining layer or other strata that would prevent water from infiltrating into the principal aquifer, whereas the injection well is completed within the target aquifer zone; (2) the well has already been drilled and has been constructed in a manner that will allow injecting water; and (3) aquifer tests have been conducted on the well and consequently, the hydrogeologic properties of the aquifer near the well are known.