Q2. What is non-potable groundwater?

Q3. What is an aquifer?

Q4. What is "groundwater not in an aquifer?"

Q5. What is "perched groundwater?"

Q6. Can the groundwater pathway be eliminated if everyone is on municipal drinking water?

Q7. How will sites which have commingled releases under Part 201 and Part 213 be handled by the DEQ?

Q8. Can the surface water pathway be eliminated if there is no surface water nearby?

Q9. If groundwater contamination has moved off-site, what is the obligation of the owner/operator (O/O) to sample off-site potable wells?

Q10. What are well head protection zones?

Q11. What are the requirements for a local ordinance to restrict the use of the groundwater?

Q12. What are the recommended procedures for abandonment of wells?

Q1. What is the definition of potable groundwater?

A. Potable groundwater is groundwater that is suitable and in sufficient quantity for human, animal and plant consumption, irrigation, and other

uses within the residential, commercial and industrial categories. All potable groundwater must be protected for health based or aesthetic criteria, whichever is more restrictive. 

Q2.What is non-potable groundwater?

A. Non-potable groundwater is groundwater that is deemed unsuitable for the uses specified in Question 1 due to naturally occurring elements and/or dissolved salts present in the groundwater. Non-potable groundwater could act as a transport mechanism to affect human or other receptors such as surface waters or other environmental areas or species. Non-potable groundwater may become potable if currently available treatment technologies are available to render the groundwater potable.

A. An aquifer is a formation capable of yielding a sufficient quantity of potable or non-potable groundwater to wells or springs.

Q4. What is "groundwater not in an aquifer?"

A. "Groundwater not in an aquifer" is water that exists in a saturated state below the ground surface but is of insufficient quantity to act as a transport mechanism or a pathway to affect a potential receptor in its natural state. Subsurface investigative or geophysical activities, supplemented by information obtained from published reports and/or investigations at nearby facilities, should be performed to document that the stated condition exists, and that there isn’t any hydraulic communication with other aquifer(s), exposure pathways or receptors. (NOTE: Permeable backfill, e.g., in buried utility trenches, may create a preferential pathway that could act as a transport mechanism to affect a receptor.) Conditions may exist in certain areas of the state where the groundwater may be used as a private potable water supply by the use of "crock wells." Contact should be made with the local health department to identify these areas.

Q5. What is "perched groundwater?"

A. "Perched groundwater" is a zone of saturation in a formation that is discontinuous from the water table and the unsaturated zones surrounding this formation. The formation exists as a discrete saturated zone that may be ephemeral (in direct response to precipitation in the immediate vicinity) or recharged by percolation from nearby surface water or other perched water zones. The hydrogeologic investigation, supplemented by published reports and/or hydrogeologic investigations at adjacent facilities, should document that the stated condition exists, and that there isn’t any hydraulic communication with other aquifer(s), exposure pathways or receptors. (NOTE: Permeable backfill, e.g., in buried utility trenches, may create a preferential pathway that could act as a transport mechanism to affect a receptor.) Perched groundwater may be a source of potable groundwater.

Q6. Can the groundwater pathway be eliminated if everyone is on municipal drinking water?

A. No. By statute groundwater is considered waters of the state and as such is protected for all uses. Only under the conditions specified in Section 21310a of Part 213 can the use of the groundwater be restricted. Also, it should be noted that many municipal water supplies depend on groundwater and as such, groundwater must be considered an exposure pathway in these cases. Some areas that are served by municipal water supplies may still have existing potable or non-potable water supply wells that were "grandfathered in."

Q7. How will sites which have commingled releases under Part 201 and Part 213 be handled by the DEQ?

A. Documentation must be provided that the contamination is commingled. The O/O can determine under which environmental program (Part201 or Part 213 )remedial activities will be performed. A written request must be provided to the department indicating under which authority corrective action activities will be conducted.

Q8. Can the surface water pathway be eliminated if there is no surface water nearby?

A. Yes, provided there are no conduits (e.g., storm sewers and utility trench backfill) or other transport mechanisms that could convey the contaminants from the site to a surface water body.

Q9. If groundwater contamination has moved off-site, what is the obligation of the O/O to sample off-site potable wells?

A. In order to determine if off-site receptors are impacted, selected potable wells that potentially could be impacted should be sampled by the O/O. Non-potable water supply wells that may intercept the groundwater contaminant plume should also be sampled. These results should be reported to the STD project manager. If contamination is detected in the potable and non-potable wells, the STD project manager and local health department should be notified immediately.

Q10. What are wellhead protection zones?

A. Wellhead protection zones are areas within the influence of the municipal well(s) that are protected from environmental impacts. Currently there are several municipalities that utilize groundwater that have defined wellhead protection zones. When conducting the initial assessment, the Underground Storage Tank Quality Consultant (QC) should identify whether the municipality has a designated wellhead protection zone. The DEQ website has a list of communities with wellhead protection zones.

Q11. What are the requirements for a local ordinance to restrict the use of the groundwater?

A. Section 21310a (3) (a) and (b) are required in an ordinance in addition to the provisions to reliably restrict the use of the groundwater for drinking. It is unlikely that any existing ordinance meets all these conditions presently.

 

Q12. What are the recommended procedures for abandonment of wells?

A. The DEQ does not have regulations covering the abandonment of groundwater monitoring wells. The DEQ recommends the use of the ASTM International Guide D5299-99 Standard Guide for Decommissioning of Ground Water Wells, Vadoze Zone Monitoring Devices, Boreholes, and Other Devices for Environmental Activities. For further information on well abandonment check the Nebraska Department of Health Guidelines for Decommissioning Water Wells.