ALABAMA GROUNDWATER SUSTAINABILITY: A STRONG SCIENTIFIC FOUNDATION

FOR WATER RESOURCE MANAGEMENT AND POLICY TO

SECURE ALABAMA’S WATER FUTURE

Marlon Cook

Geological Survey of Alabama Groundwater Assessment Program

Alabama Water Policy Development Alabama is essentially a raparian rights state. The Alabama Water Resources Act of 1993 created the Alabama Office of Water Resources, which maintains a Certificate of Beneficial Use Program that tracks water use of >100,000 gallons per day. In 2008 Act No. 2008-164 created the Permanent Joint Legislative Committee on Water Policy and Management. In 2011 Governor Robert Bentley created the Alabama Water Agencies Working Group (AWAWG) comprised of the: Alabama Office of Water Resources Alabama Department of Environmental Management Alabama Department of Conservation and Natural Resources Alabama Department of Agriculture and Industries Geological Survey of Alabama In 2013, the Alabama Permanent Joint Legislative Committee on Water Policy and Management mandated the Geological Survey of Alabama and the Alabama Office of Water Resources to perform scientific assessments of the state’s water resources.

Alabama Water Resource Policy and Management

A Clean Slate?

Alabama Water Policy?

Effective Water Management and Policy Must be Based on Sound

Scientific Data

WHY IS GROUNDWATER IMPORTANT IN

ALABAMA?

Source of water-use data,

USGS-OWR Estimated Use of Water in Alabama 2005

40% of public water supply by volume is from groundwater sources.

70% of the geographic area of Alabama is supplied by groundwater sources.

Assessments for Water Resource Management and Policy Development: The Big Picture

Effective statewide water management is founded on a number of integrated

components that include: Acquisition of fundamental water resources data including:

Water Availability Assessments—Determine how much water of sufficient quality is available from surface and groundwater sources, current impacts of water production, quantities of sustainable yield, and strategies for future water source development. Consumptive Water Use Assessments—Determine how much water is currently used in specified sectors of society, how much water is returned to the environment, forecasts of future water use, and strategies for more efficient water production and use. Instream Flow Assessments—Determine how much water should remain in surface channels to support fish and wildlife and the functions of natural hydrologic systems, and impacts of current and future climate and water production.

Establish statewide surface-water and groundwater monitoring networks including: A comprehensive water resource monitoring network comprised of strategically located real-time and periodic groundwater level, surface-water discharge, and precipitation monitoring systems, designed to assess climate and water production impacts.

State-Wide Groundwater Assessment

Areas

Groundwater Assessments: HYDROGEOLOGIC COMPONENTS Well location maps (water wells and oil and gas production and test wells will be sources of data for investigations).

Hydrogeologic well data (includes well depth, depth to water, pumping rates, and specific capacity). Stratigraphic analyses including mapping and cross sections (includes geophysical log evaluation, well sample analysis, and seismic interpretations). Structure maps (elevation of the top of each assessed aquifer and location of geologic structures that influence water occurrence including fault and fracture identification. Structural investigation will include geophysical log analysis, gravity and magnetics, and seismic acquisition and interpretation). Net potential productive interval isopach maps for all major coastal plain aquifers (net aquifer productive interval isopach maps indicate depositional trends and the water bearing potential of geologic units).

Aquifer productivity characteristics includes specific capacity, pumping rates, and depth to water maps. Potentiometric surface/water table, and residual drawdown maps (indicates groundwater flow paths, production impacts, and climatic impacts). Ground-water production impact maps (indicates production stress on each assessed aquifer based on water

levels and well contribution area models). Probable sustainable yield maps (based on available aquifer test data).

Aquifer recharge estimates (quantitative estimate of recharge for each assessed aquifer including stream base-flow assessments and character of surface- ground-water interaction).

Groundwater storage estimates (quantitative estimate of in-situ water storage in individual aquifers.

Alabama Water Well Data

GSA is the repository for Alabama water well data. More than 125,000 well records including construction, lithologic, pump testing, geophysical logs, and geochemical analyses. Most records are scanned and data is currently being input to excel spreadsheets.

Alabama RBDMS-Environmental Database Development

• The GSA GAP with GWPC and its developers to develop an RBDMS-E database to house Alabama’s water well and groundwater research data.

• These data will be displayed in an interactive mapping system similar to the Alabama OGB.

• The GSA GAP RBDMS-E Database along with a similar database to be developed for the Alabama Office of Water Resources will provide the foundation for Alabama Water Resource Management and Policy development.

Alabama Groundwater Research

Statewide

Groundwater Assessment

Area 1

Generalized Stratigraphy Southeast Alabama

Major Aquifers

Minor Aquifers

Potential New Aquifer

Stratigraphic Analysis

Net Potential Productive

Interval Mapping

∑ = 74 ft 75%

Nanafalia Formation

GR Resistivity

Net Potential

Productive Interval Isopach

Map Clayton Aquifer

Net Potential

Productive Interval Isopach

Map Gordo Aquifer

Initial Potentiometric

Surface Map

Clayton Aquifer

Pre 1970

Current Potentiometric

Surface Map

Clayton Aquifer

Production Impact

Map

Aquifer

Range of residual

drawdown (feet)

Average capture zone

area (mi2)

Optimum well spacing (miles)

Along strike of hydraulic gradient

direction

Up or down gradient direction

Gordo 0-154 1.9 1.5 2.0

Ripley 0-149 2.6 1.0 2.5

Clayton 0-204 2.0 1.0 2.0

Nanafalia 0-189 1.2 1.0 2.0

Tallahatta 1-119 0.5 1.0 1.5

Tuscahoma 31-119 3.5 1.5 2.5

Lisbon 0-33 0.6 1.0 1.0

Crystal River 0-27 1.0 1.0 1.0

Well capture zone and spacing data for southeast Alabama aquifers

Components of Groundwater Recharge

Aquifer Recharge Areas

Aquifer Recharge

Aquifer Recharge

Area (mi2) Million g/d Gallons/d/mi2 In/yr

Tuscaloosa Group 643 106.3 165,300 4.4

Eutaw Formation 445 121.9 273,900 5.8

Cusseta Member Ripley Formation 267 32.9 123,200 2.6

Ripley Formation 453 61.8 136,400 2.9

Providence Formation 569 29.0 51,000 1.1

Clayton Formation 461 78.3 169,800 3.7

Nanafalia Formation 563 133.9 237,800 5.0

Lisbon and Tallahatta Formations 1,129 269.9 239,100 5.0

Crystal River Formation 1,683 408.4 242,700 5.1

Unconfined or partially confined recharge for aquifers in the Southeast Alabama pilot project area

Aquifer Transvissivity

(ft2/d) Thickness

(ft) Hydraulic

Gradient (ft/mi) Recharge

(million gal/d)

Gordo Formation 3,000 175 3.3 6.5

Ripley Formation 7,500 100 11.4 37.8

Clayton Formation 10,000 150 7.5 48.1

Nanafalia Formation 4,470 50 8.3 24.6

Confined recharge for selected aquifers in the Southeast Alabama pilot project area

0 50 100 150 200 250 300 350 400 450

Tuscaloosa Group/Gordo

Eutaw

Providence

Cusetta

Ripley

Clayton

Nanafalia

Crystal River

Aqui

fer

Recharge (Mgd)Confined Recharge VolumeUnconfined Recharge Volume

Recharge volumes for unconfined and confined zones of major aquifers in the southeast Alabama project area

Groundwater in Subsurface Storage

Aquifer

Average effective porosity (percent)

Confined aquifer area (fresh water)

(mi2)

Aquifer potential

productive interval

thickness (ft)

Storativity

Available groundwater in storage

(million ft3) (million gal)

Lower Cretaceous 28 2,400 350 0.0000044 294.4 2,202.4

Coker Formation 32 4,500 210 0.0000026 293.6 2,196.1

Eutaw and Gordo Formations 36 4,000 175 0.0000030 281.0 2,102.3

Ripley Formation 30* 4,600 100 0.0000013 58.4 436.5

Clayton Formation and Salt Mountain Limestone

40* 1,980 325 0.0000019 124.5 931.2

Nanafalia Formation 30* 2,900 50 0.00000062 15.6 116.5

Storativity, related aquifer characteristics, and available groundwater in storage for major confined aquifers in the project area

When storativity is multiplied by the surface area overlying an aquifer and the average hydraulic head above the stratigraphic top of a confined aquifer, the product is the volume of available groundwater in storage in a confined aquifer (Fetter, 1994): Vw = SA h

GSA GAP Web Site

GSA GAP Real-Time

Groundwater Monitoring

System

Real-Time Hydrograph

Location: Jefferson County Aquifer: Bangor Limestone Depth of Well: 140 BLS Land Surface Elevation: 642 feet AMSL Period of record for percentiles: 1975-2012

Periodic Monitored Wells

For more information: Marlon Cook Director, Groundwater Assessment Program Geological Survey of Alabama 205-247-3692 www.gsa.state.al.us/