TECHNICAL PRESENTATION FOR THE CACHE CRITICAL GROUND WATER AREA

Background

In February of 1991, the General Assembly of the State of Arkansas passed into law the Arkansas Ground Water Protection and Management Act, or Act 154 if 1991. This law mandated that the Arkansas Natural Resources Commission (ANRC) evaluate the condition of the State’s aquifers on a biennial basis, and make recommendations concerning the designation of critical ground water areas. The ANRC works with the Arkansas District of the U.S. Geological Survey, the Natural Resource Conservation Service, and the Arkansas Geological Commission to monitor water levels and water quality in a network of over 1400 wells Statewide, in order to make this evaluation of the State’s ground water resources.

The designation of a critical ground water area allows federal, State, and local groups to work together in providing a managed and protected resource for current and future water users by focusing on conservation and education. Critical area designation also allows State and federal agencies to focus cost share and tax incentives for conservation projects within those areas. Critical area designation does not involve regulation or allocation of water use or well drilling.

Since enactment of the Arkansas Ground Water Protection and Management Act, the ANRC has designated two critical ground water areas in Arkansas. The first critical ground water area was delineated in a five county area in South Arkansas for the Sparta Sand formation. The second area was designated in a six county area surrounding the Grand Prairie in East-Central Arkansas for the alluvial and Sparta Sand formations.

As of July 27^th, 2009, the ANRC has received notification of a petition from six counties in northeastern Arkansas requesting to be designated as a critical ground-water area. These counties include Clay, Craighead, Cross, Greene, Poinsett, and St. Francis counties. At this request, the staff of the ANRC has evaluated these counties with respect to critical area criteria in accordance with the Ground Water Protection and Management Act of 1991, and has determined that the portion of these counties laying west of Crowley’s Ridge do in fact meet the criteria for designation. It is hereby recommended that the western portion of these six counties, as delineated in this report, be designated as critical ground water areas for the Mississippi River Valley alluvial aquifer and the Memphis Sand aquifer.

Critical Area Criteria

In accordance with Section 403.1 of the Ground Water Protection and Management Report of 1991, the ANRC staff will consider the following criteria for critical area designation:

Using all pertinent data, an analysis will be made to determine those areas that have developed, or trends indicate they may develop, significant ground water depletion and/or degradation. Designating an area indicates that limitation of withdrawals through the use of water rights may be necessary in order to maximize the present and continued beneficial use of the area’s remaining ground water resources.

A. Criteria used in an analysis leading to a recommendation of a critical ground water area will consist of, but not be restricted to, the following parameters:

1. Water Quantity:

(a) For water table conditions (unconfined aquifer): Average decline of one (1) foot or more have occurred annually for a minimum of five (5) years and/or water levels have been reduced such that fifty percent (50%) or less of the formation is saturated.

(b) For artesian conditions (confined aquifer): Average declines of one (1) foot or more have occurred annually for a minimum of five (5) years and/or the potentiometric surface is at or below the top of the formation.

2. Water Quality: Ground water quality has been degraded or trends indicate probably future degradation that would render the water unusable for the beneficial uses of the aquifer.

3. Projections/Hydrologic Boundaries: Consideration will be given to a safe yield of ground water pumping strategy for the aquifer including the utilization of a ground-water flow model, the natural hydrologic boundaries of the aquifer, and projected water-level declines.

B. A report shall be prepared based on criteria in Section 403.1 A as well as specific geologic and hydrologic characteristics of the area judged by Commission staff to warrant inclusion. The report shall contain a map showing recommended boundaries and the explanation of proposed action.

C. A public hearing will then be conducted within each county of the proposed area in accordance with the Administrative Procedures Act.

D. After consideration of all evidence, public comments, and recommendations of Commission staff, the Commission may issue an order designating the critical ground water areas and the boundaries thereof.

Currently, water use from the alluvial aquifer in the proposed Cache Critical Ground Water Area is at an approximate rate of which only 43 percent is sustainable and 57 percent is unmet demand. As a result of this unsustainable pumping rate, ground water is being captured from streamflow and other sources, and water-levels are declining at a rate of over one foot per year throughout the proposed Cache CGWA. Water-level declines and sustainable yield data supporting the critical area designation for the proposed area are presented in the attached figures of this report.

Critical Area Boundary

The Cache Hydrogeologic Unit Critical Ground Water Area of Northeastern Arkansas will include the alluvial and Memphis Sand aquifers of the western portions of Clay, Craighead, Cross, Greene, Poinsett, and St. Francis counties laying west of the formations making up Crowley’s Ridge as defined on the Geologic Map of Arkansas, 1993.

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