Overview of Water Availability in Mississippi

Transcription

1 Overview of Water Availability in Mississippi April 6, 2016 Pat Phillips, RPG MDEQ - OLWR

2 Mississippi s Abundant Water Resources Groundwater Surface Water

3 Average Annual Precipitation in Mississippi

4 Surface Water Resources in Mississippi Mississippi has 86,000 miles of rivers and streams in 10 major river basins: Big Black River Coastal Streams Northern Independent Streams Pascagoula River Pearl River Lower Pearl River South Independent Streams Tennessee River Tombigbee River Yazoo River

5 Groundwater Resources in Mississippi 18+ major aquifers Multiple aquifers available in most areas of state Variable water quality & quantity in some places issues with color, iron, chlorides or amount of water that can be obtained. Complex hydrogeology Water management challenges.

6 Water Mentality We take our abundant water resources in Mississippi for granted. Since we do seem to have so much water, we believe that the cost of water should be low. When water is plentiful and cheaply priced (or free), we have a tendency to waste it. Human nature is to worry about droughts only when we are in the middle of one and our memory of droughts is often of short duration. We believe we will never run out of water.

7 Mississippi s Reliance on Groundwater Estimated use from the 2010 USGS National Water Use Information Program: 3.9 billion gallons of water each day. According to the USGS, the largest use of surface water is for once through and closed loop cooling for the generation of electricity. 2.6 billion gallons of groundwater are used each day ( 67% of total). Irrigation and aquaculture account for > 79% of the groundwater used in the state.

8 Why Groundwater versus Surface Water? Groundwater is more reliable during droughts. Generally, groundwater needs less treatment before use. Drilling a well is less expensive than building a water treatment plant. Groundwater can be tapped where it is needed, whereas surface waters are concentrated in lakes and streams. Groundwater is less susceptible to contamination. The amount of groundwater available in Mississippi dwarfs the amount of surface water available.

9 Prioritization of Beneficial Use Drinking water supply is designated as the highest priority of use. Other beneficial uses (irrigation, industrial, fish culture, commercial, etc.) receive a lower priority. It is fortunate that our agricultural users in the Delta are usually not in direct competition with potable water supplies.

10 Drinking Water Supply in Mississippi PWS Wells in Mississippi Over 90% of the supply is derived from groundwater resources. Over 100,000 domestic wells 1,100+ public water systems ( 2,700 wells). Only 5 public surface water systems operating in the state.

11 Location of Surface Water Public Water Supply Intakes

12 Surface Water Management Tools Regulate surface water withdrawals: currently there are 2,549 active surface water diversion permits. When flows in rivers and streams begin to drop, OLWR monitors flow to determine whether permitted diversions must cease. Work with the Office of Pollution Control by measuring streamflow where OPC samples for MS Benthic Index of Stream Quality (MBISQ). Work with the MS Department of Health and the Office of Pollution Control to develop source water protection plans for the surface water public water supplies.

13 Groundwater Management Tools Compile aquifer-specific water-use information; Measure and record water-level declines in aquifers, which includes developing potentiometric maps for a particular aquifer; Monitor groundwater quality; Conduct hydrogeologic investigations of aquifers, which includes creating cross-sections and maps; Regulate groundwater withdrawal (permits); Use all available groundwater resources; and Advance use of alternative water sources.

14 What s Geology Got to Do with Groundwater? Everything! Dumping ground for the North American Continent Mostly unconsolidated beds of sand, gravel and/or clay Variable state geology Can affect water quality Water rich and water poor areas in the state

15 Source Water Assessment Program In 1998, the MS Department of Health contracted with MDEQ to develop and administer the Source Water Assessment Program. MDEQ assesses the relative susceptibility of public water supply wells to becoming contaminated using various criteria, including well construction, aquifer confinement, pumpage, and flow direction, as well as proximity to possible contaminants. Three rankings: Higher, Moderate, and Lower Capture zone around PWS well

16 Agricultural Chemical Monitoring Program MOU with the MS Department of Agriculture and Commerce Sample wells all over the state for possible contamination by agricultural chemicals Publish annual report of findings To date, over 1,800 total samples have been collected from almost 1,300 wells.

17 Ambient Water Level Monitoring Network Plan to have two wells in each aquifer in every county. Each well will be measured yearly. Will add wells or remove wells from network as necessary.

18 Areas of Hydrogeologic Investigation

19 Northern Region Encompasses 18 counties Groundwater flow model of the Cretaceous and Paleozoic aquifers Potentiometric maps of the Cretaceous and Paleozoic aquifers Potentiometric Map of the Eutaw-McShan

20 The Delta 18 counties encompassing 7,000 square mile Mississippi River alluvial plain Currently working with the USGS on a groundwater flow model of the MRVA Refining delineation of the underlying Tertiary aquifers

21 Encompasses 20 counties, including the Jackson Metro area Central Region Potentiometric maps of the Wilcox aquifers Work on developing cross-sections and maps

22 Southern Region Encompasses 24 counties Water quality and water level monitoring network on the coast Work on delineating the Miocene aquifers Fracking in southwest Mississippi

23 Why Do We Need Detailed Information on Our Water Resources? We can t manage our water resources responsibly unless we know as much about them as possible. Agriculture is Mississippi s number one industry, employing approximately 29% of the state s workforce either directly or indirectly. Agriculture in Mississippi is a 7.4 billion-dollar industry. There are approximately 37,100 farms in the state covering 10.9 million acres. As noted earlier, irrigation and aquaculture account for over 2 billion gallons per day of groundwater used in the state every year. Economic development: Preliminary siting of proposed projects often do not adequately consider the availability of water resources. Selected development sites are often predetermined because of other factors such as transportation and energy considerations. People in Mississippi like to fish, go boating, and swim in our rivers and lakes.

24 Alternative Water Supplies Must consider both the water quality and quantity needs of projects. Using surface water resources instead of groundwater; Using deeper aquifers with poorer water quality not being used for potable supply; Treatment of brackish water to drinking water standards: or Using effluent discharge from municipal waste water treatment facilities.

25 Conclusions Mississippi has an abundant supply of water both groundwater and surface water. The only way to manage a resource is to know as much about it as possible. Drinking water takes priority over all other beneficial uses. We encourage the conjunctive use of groundwater and surface water sources whenever possible. Effective water management is paramount to our future.

26 Mississippi Department of Environmental Quality Office of Land and Water Resources Pat Phillips, RPG Water Resources Management Division P.O. Box 2309 Jackson, MS