RISK-BASED CORRECTIVE ACTION - WATER WELL SURVEYS

Hazardous Waste Program fact sheet
12/2015
Division of Environmental Quality Director: Ed Galbraith
PUB2402

Missouri has two Risk-Based Corrective Action (RBCA) processes. One pertains solely to releases from petroleum storage tanks and is referred to as the Tanks RBCA. The other pertains to non-petroleum storage tank releases and is referred to as the departmental RBCA.

Under either process, if contaminants have or are likely to reach groundwater, a groundwater evaluation must be conducted to determine whether, to what extent, and how groundwater is being or is likely to be used. Because the presence of public or private water wells is a clear indication groundwater is being used as part of an overall groundwater evaluation, the RBCA processes require evaluating parties conduct a water well search at and near the site of contamination.

The list below identifies those sections of the Missouri Department of Natural Resource’s RBCA Process rule, 10 CSR 25-18.010 and the departmental and Tanks RBCA guidance documents where the water well identification requirements are found.

The identification of water wells is critical to accurately assessing the risk associated with groundwater contamination and collection of the information necessarily precedes the risk assessment.

Specific Water Well Survey Requirements
When warranted under both RBCA processes, a water well survey must identify:

In general, well surveys shall include a review of local, state and federal records pertaining to well installations and operation and water sources.  Those conducting water well surveys should bear in mind, prior to July 1987; certification of non-public water wells was not required in Missouri and occurred solely on a voluntary basis.  As a result, water well records are incomplete.  Therefore, in most cases, a physical door-to-door survey of the site and nearby properties will be necessary to more definitively determine whether water wells are present within the prescribed search distances. Both RBCA processes recognize and address this potential (see subsection 6.5.3 in the departmental RBCA guidance and 5.5.4 and 5.5.1 in the Tanks RBCA 2004 and 2013 guidance documents, respectively).

When evaluating actual and potential groundwater use and conducting well surveys, consultants and other environmental professionals should consider not only the potential for domestic use of groundwater (e.g., drinking and bathing), but also industrial, irrigation (both large scale agricultural and small scale watering of gardens), livestock and other potential uses. In some cases, even though a community water distribution system may be in place, local individuals might still use groundwater and might access the groundwater via hand dug and other shallow wells, in addition to typical drilled and cased wells. Hand dug and other shallow wells are unlikely to appear in certification records and are most likely to be discovered only through door-to-door surveys. When conducting such surveys, questions should be fashioned to obtain information about both domestic and non-domestic uses of groundwater.

Department of Natural Resources Well Survey Information
The department maintains many records related to public and private water wells.

However, as stated above, these records may not contain information on non-public wells installed prior to July 1987. The department’s well records can be obtained from the following sources.

Other Resources
The United States Geological Survey, or USGS, is also a resource for well information. Local city or county governmental entities, in particular local health departments, might be a source of valuable information regarding water wells and other water systems within their jurisdictional boundaries. In addition to well and water system information, local governmental entities might also have information about public water supply systems and local ordinances pertaining to water well construction, installation, and operation.

Finally, residents, particularly long-time residents, can be a valuable source of information regarding water wells at and near a specific site. Door-to-door surveys, as mentioned above, are a good way to find residents who might be a source of such information.

Survey Limitations
None of the information sources discussed herein should be considered, by themselves, as comprehensive sources of well location and construction information. The department is aware many wells, both active and inactive, exist for which the department and other entities have no records. Numerous water wells were installed before non-public well certification requirements became effective in July 1987, while others might have been installed in violation of certification requirements. The department recommends well surveys include more than one source of information and a physical survey of the site and surrounding area. When in doubt regarding the need for or the required extent of a water well survey, contact the department’s Hazardous Waste Program at 573-751-3176.

The water well survey requirements discussed here are the minimum standards under the RBCA processes. The department may require additional or different actions depending on the technical or legal framework applicable to a specific site.

Additional Information
Departmental RBCA Technical Guidance Document http://dnr.mo.gov/env/hwp/mrbcadocument.htm
GeoSTRAT http://dnr.mo.gov/geology/geostrat.htm
MRBCA Web page http://dnr.mo.gov/env/hwp/mrbca.htm
Risk-Based Corrective Action Process for Petroleum Storage Tanks (2004) http://dnr.mo.gov/env/hwp/docs/tanks-2004-guidance.pdf
Risk-Based Corrective Action Process for Petroleum Storage Tanks (2013) http://dnr.mo.gov/env/hwp/tanks/mrbca-pet/docs/tanks-final-guidance2013.pdf
Tanks RBCA Web page http://dnr.mo.gov/env/hwp/tanks/mrbca-pet/mrbca-pet-tanks.htm
U.S. Geological Survey http://waterdata.usgs.gov/nwis
Water Resources Center http://dnr.mo.gov/geology/wrc/?/env/wrc/
Well Information Management System (WIMS) https://dnr.mo.gov/mowells/
Missouri Code of State Regulations for Department of Natural Resources http://www.sos.mo.gov/adrules/csr/current/10csr/10csr