Minnesota Administrative Rules
Agency 144 - Health Department
Chapter 4720 - PUBLIC WATER SUPPLIES
WELLHEAD PROTECTION
Part 4720.5100 - DEFINITIONS

Universal Citation: MN Rules 4720.5100

Current through Register Vol. 49, No. 13, September 23, 2024

Subpart 1. Scope.

The terms used in parts 4720.5100 to 4720.5590 have the meanings given them in Minnesota Statutes, section 103I.005 and in this part.

Subp. 2. Angle of ambient groundwater flow.

"Angle of ambient groundwater flow" means the direction of groundwater flow through an aquifer undisturbed by pumping or human-caused activities. The angle of ambient groundwater flow is expressed in degrees, ranging from 0 to 360 degrees, and is measured in a clockwise direction from geographical north, not magnetic north.

Subp. 3. Aquifer.

"Aquifer" has the meaning given in part 4725.0100, subpart 21.

Subp. 4. Aquifer test plan.

"Aquifer test plan" means the document containing the plan by which the aquifer transmissivity value will be calculated for a public water supply well, as required under part 4720.5540.

Subp. 5. Casing.

"Casing" has the meaning given in part 4725.0100, subpart 22.

Subp. 6. Commissioner.

"Commissioner" means the commissioner of health.

Subp. 7. Community water supply.

"Community water supply" has the meaning given to "community water system" in Code of Federal Regulations, title 40, section 141.2 (1992 and as subsequently amended).

Subp. 8. Confined aquifer.

"Confined aquifer" has the meaning given in part 7045.0020, subpart 10.

Subp. 9. Confining layer.

"Confining layer" has the meaning given in part 4725.0100, subpart 24a.

Subp. 10. Contamination.

"Contamination" has the meaning given in part 4725.0100, subpart 34.

Subp. 11. Contingency strategy.

"Contingency strategy" means the part of a wellhead protection plan that describes an organized, planned, and coordinated course of action that identifies the location and provision of an alternate drinking water supply if the public water supply is disrupted by mechanical failure or contamination.

Subp. 12. Department.

"Department" means the Minnesota Department of Health.

Subp. 13. Drinking water supply management area.

"Drinking water supply management area" means the surface and subsurface area surrounding a public water supply well, including the wellhead protection area, that must be managed by the entity identified in a wellhead protection plan. The boundaries of the drinking water supply management area are:

A. center lines of highways, streets, roads, or railroad rights-of-way;

B. section, half-section, quarter-section, quarter-quarter-section, or other fractional section lines of the United States public land survey;

C. property or fence lines;

D. the center of public drainage systems;

E. public utility service lines; or

F. political boundaries.

Subp. 14. Drinking water supply management area vulnerability.

"Drinking water supply management area vulnerability" means an assessment of the likelihood for a potential contaminant source within the drinking water supply management area to contaminate a public water supply well based on:

A. the aquifer's inherent geologic sensitivity; and

B. the chemical and isotopic composition of the groundwater.

Subp. 15. Flow boundaries.

"Flow boundaries" means hydrologic or geologic boundaries, including:

A. the physical limits of an aquifer;

B. lakes, rivers, streams, drainage ditches, or other surface hydrologic features;

C. areas of contrasting geologic materials; or

D. the pumping influence of other wells.

Subp. 16. Geographic reference point.

"Geographic reference point" means a location on the earth's surface that is referenced in:

A. latitude and longitude;

B. a universal transverse mercator projection;

C. the public land survey system; or

D. the state plane coordinate system.

Subp. 17. Groundwater.

"Groundwater" has the meaning given in Minnesota Statutes, section 115.01, subdivision 6.

Subp. 18. Hydraulic gradient.

"Hydraulic gradient" means the slope of the water table or potentiometric surface.

Subp. 19. Inner wellhead management zone.

"Inner wellhead management zone" means the land within a 200-foot radius of a public water supply well.

Subp. 20. Isolation distance.

"Isolation distance" means the distance from a contamination source as described in parts 4725.4450 and 4725.5850.

Subp. 21. Local unit of government.

"Local unit of government" has the meaning given in part 8405.0110, subpart 5.

Subp. 22. Municipal public water supply well.

"Municipal public water supply well" means a public water supply well owned, managed, or operated by a municipality as defined in Minnesota Statutes, section 103B.305, subdivision 6.

Subp. 23. Noncommunity water supply.

"Noncommunity water supply" has the meaning given to "noncommunity water system" in Code of Federal Regulations, title 40, section 141.2 (1992 and as subsequently amended).

Subp. 24. Nontransient noncommunity water supply.

"Nontransient noncommunity water supply" has the meaning given to "nontransient noncommunity water system" in Code of Federal Regulations, title 40, section 141.2 (1992 and as subsequently amended).

Subp. 25. Official controls.

"Official controls" has the meaning given in part 8405.0110, subpart 7.

Subp. 26. Potential contaminant source.

"Potential contaminant source" means any human-related activity that presents a risk to groundwater quality.

Subp. 27. Public water supplier or supplier.

"Public water supplier" or "supplier" has the meaning given to "supplier of water" in Code of Federal Regulations, title 40, section 141.2 (1992 and as subsequently amended).

Subp. 28. Public water supply or supply.

"Public water supply" or "supply" has the meaning given to "public water system" in Code of Federal Regulations, title 40, section 141.2 (1992 and as subsequently amended).

Subp. 29. Public water supply well.

"Public water supply well" means a well as defined in Minnesota Statutes, section 103I.005, subdivision 21, that serves a public water supply and is not a dewatering well or a monitoring well serving a public water supply.

Subp. 30. Pumping discharge rate.

"Pumping discharge rate" means the volume of water discharged by a well per unit of time.

Subp. 31. Pumping test.

"Pumping test" means a test, as described in parts 4720.5520 and 4720.5530, that is used to determine the aquifer transmissivity.

Subp. 32. Related land resources.

"Related land resources" has the meaning given in Minnesota Statutes, section 103B.305, subdivision 8.

Subp. 33. Remaining portion of the wellhead protection plan.

"Remaining portion of the wellhead protection plan" means that portion of the wellhead protection plan that remains to be completed after the public water supplier has fulfilled the requirements of parts 4720.5320 and 4720.5330.

Subp. 34. Specific capacity test.

"Specific capacity test" means the productivity of a well obtained by dividing the gallons of water pumped per unit time by the number of feet the water level in the well is lowered due to its pumping.

Subp. 35. State identifier.

"State identifier" means the unique number assigned by the department to a well or the number assigned by a state agency responsible for a potential source of contamination.

Subp. 36. Time of travel.

"Time of travel" means the amount of time over which groundwater will move through a portion of an aquifer and the overlying geologic materials to recharge a well in use.

Subp. 37. Transient noncommunity water supply.

"Transient noncommunity water supply" means a public water supply that is not a community water supply or a nontransient noncommunity water supply.

Subp. 38. Transmissivity.

"Transmissivity" means the product of the average hydraulic conductivity and the saturated thickness of the aquifer. Hydraulic conductivity means the volume of water that will move through a porous medium in unit time under a unit hydraulic gradient through a unit area measured at right angles to groundwater flow.

Subp. 39. Unconfined aquifer.

"Unconfined aquifer" has the meaning given in part 6115.0630, subpart 17.

Subp. 40. Watershed district.

"Watershed district" means a district established under Minnesota Statutes, chapter 103D.

Subp. 41. Watershed management organization.

"Watershed management organization" has the meaning given in Minnesota Statutes, section 103B.205, subdivision 13.

Subp. 42. Well vulnerability.

"Well vulnerability" means an assessment of the likelihood of contamination entering a public water supply well based on the criteria specified in part 4720.5550, subpart 2.

Subp. 43. Wellhead protection.

"Wellhead protection" means a method of preventing well contamination by effectively managing potential contaminant sources in all or a portion of the well's recharge area.

Subp. 44. Wellhead protection measure.

"Wellhead protection measure" means a method adopted and implemented by a public water supplier to prevent contamination of a public water supply, and approved by the department under parts 4720.5110 to 4720.5590.

Subp. 45. Wellhead protection plan or plan.

"Wellhead protection plan" or "plan" means a document that provides for the protection of a public water supply, is submitted to the department, is implemented by the public water supplier, and complies with:

A. the wellhead protection elements specified in the 1986 amendments to the federal Safe Drinking Water Act, United States Code, title 42, chapter 6A, subchapter XII, part C, section 300h-7 (1986 and as subsequently amended); and

B. parts 4720.5200 to 4720.5290.

Statutory Authority: MS s 103I.101

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