Statewide Ground Water Quality Monitoring Network: Providing Insight into Human Impact on some Shallow Aquifers
What is it? It is an array of 145 wells at 80 monitoring sites in 25 shallow, sensitive aquifers.
Is our drinking water safe? We have many aquifers that occur at or very near land surface Naturally occurring constituents in the rocks may present a concern We conduct activities over these aquifers that could put the shallow ground water and surface water at risk
Goals of the monitoring effort To monitor: The present ground water quality The impact of agricultural chemicals on ground water Long-term trends in water quality in sensitive aquifers
Site selection criteria Must be representative of typical land use Must not be near any known or suspected point sources of pollution If possible, located in a part of the aquifer that is thick enough to accommodate nested wells Must be accessible to the drilling equipment of the Geological Survey Must be reasonably accessible in inclement weather for sampling
Number of aquifers monitored = 25 Number of monitoring sites = 80 Number of monitoring wells = 145
Sampling Frequencies Reconnaissance Sampling All wells sampled once per year, approximately the same time each year Common Inorganics - sampled each time Pesticides - sampled each time Trace Metals - all wells in every aquifer sampled once every 5 years Radionuclides - all wells in every aquifer sampled once every 5 years Volatile Organic Compounds - 25% of wells in every aquifer sampled once every 5 years
Sampling Frequencies Intensive Sampling Sampling 3 times per year in addition to yearly reconnaissance sampling Sites selected on the basis of previous detections of pesticides and/or high nitrate concentrations Nitrate, pesticides, and pesticide transformation products Nitrate only
Aquifers with an intensively sampled monitoring site (or sites) in 2005 Antelope Valley Spearfish Creek Bear Butte Creek Cow Creek Highmore- Blunt Tulare Big Sioux Skunk Creek Arikaree Delmont Vermillion- West-Fork Ogallala Missouri
Aquifers in which nitrate concentrations equal to or greater than 3 mg/l were observed in 2005 Bowdle Selby Coteau Lakes Vermillion East-Fork Antelope Valley Cow Creek Tulare Big Sioux Skunk Creek Arikaree Ogallala Delmont Vermillion- West-Fork Parker- Centerville Missouri
Aquifers in which nitrate concentrations equal to or greater than 10 mg/l were observed in 2005 Bowdle Selby Coteau Lakes Antelope Valley Cow Creek Tulare Big Sioux Skunk Creek Ogallala Delmont Vermillion- West-Fork Parker-Centerville Missouri
Nitrate concentration versus depth below water table, 1998-2004 0 water table Depth below water (feet) 10 20 30 40 drinking water standard (10 mg/l) 50 010 50 100 150 200 250 Nitrate concentration (mg/l)
250 31 200 32 150 33 100 Nitrate concentration (mg/l) 34 50 0 May 1995 May 1996 May 1997 May 1998 May 1999 May 2000 May 2001 May 2002 May 2003 May 2004 Nitrate concentration (mg/l) Nitrate concentration and depth to water versus time in well R20-94-41, Ogallala aquifer 30 Depth to water (feet) 35 drinking water standard (10 mg/l) Date Depth to water (feet)
Nitrate concentration versus time in well R20-89-42, Big Sioux aquifer 20 16 12 drinking water standard (10 mg/l) 8 4 0 Nitrate concentration (mg/l) Sep 1989 Sep 1990 Sep 1991 Sep 1992 Sep 1993 Sep 1994 Sep 1995 Sep 1996 Sep 1997 Sep 1998 Sep 1999 Sep 2000 Sep 2001 Sep 2002 Sep 2003 Sep 2004 Date
Pesticide and pesticide transformation product analytes, 2005 Acetochlor Alachlor Atrazine Desethyl atrazine Desisopropyl atrazine Bentazon Carbofuran Cyanazine 2,4-D Dicamba Glyphosate Malathion MCPA Metolachlor Metribuzin Picloram Simizine Trifluralin
Aquifers in which detectable concentrations of pesticides or pesticide transformation products were observed in 2005 Highmore- Blunt Big Sioux Skunk Creek Delmont Missouri
Pesticides and their transformation products Acetochlor Acetochlor esa Acetochlor oa Alachlor Alachlor esa Alachlor oa Metolachlor Metolachlor esa Metolachlor oa Propachlor Propachlor esa Atrazine Desethyl atrazine Desisopropyl atrazine
Trace Metals 2005 Antimony Arsenic Barium Beryllium Cadmium Chromium Copper Lead Mercury Nickel Selenium Thallium
Aquifer in which a trace metal concentration equal to or in excess of a drinking water standard was observed in 2005
Aquifer in which a trace metal concentration equal to or in excess of a drinking water standard was observed, 1994-2005 Bear Butte Creek Cow Creek Ogallala Missouri
Aquifers in which arsenic concentrations equal to or greater than 10 µg/l were observed, 1994-2005 Selby Antelope Valley Spearfish Creek Skunk Creek Arikaree Delmont Parker- Centerville Ogallala Missouri
Aquifers in which gross alpha activity may have exceeded or did exceed 15 pic/l, 1994-2005 Bowdle Okobojo Creek Cow Creek Highmore- Blunt Tulare Big Sioux Rapid Creek Skunk Creek Cheyenne River Arikaree Vermillion- West-Fork Ogallala 15 pic/l gross alpha activity in aquifer was definitely exceeded Missouri 15 pic/l gross alpha activity in aquifer may have been equaled or exceeded
Aquifers in which Radium 226 + 228 activity may have exceeded 5 pic/l, 1994-2005 Spearfish Creek Bear Butte Creek Rapid Creek Missouri
Aquifers in which concentrations of Uranium equal to or in excess of 30 ug/l were observed, 1994-2005 Tulare Big Sioux Cheyenne River Missouri
Volatile Organic Compounds (VOCs) A list of 61 VOCs is sampled for. There have been 3 detections of VOCs. The detected VOCs were xylene, chloroform, and bromodichloromethane.
Accessing data http://www.sdgs.usd.edu