214 - Well Testing - Village of Thiensville

Ordinance #214
Well Testing - Village of Thiensville


WHEREAS, the Village of Thiensville is totally dependent upon ground water; and

WHEREAS, a new well has the potential to impact existing wells if the pumps are set close to the normal pumping level of the wells; and

WHEREAS, the magnitude and extent of the impact cannot be accurately predicted without a properly controlled pumping test,

NOW, THEREFORE, The Village Board of the Village of Thiensville, Ozaukee County, Wisconsin, do ordain as follows:

Chapter 78, Article II, Division 3 WELL TESTING, Section 78-55 of the Municipal Code of Ordinances of the Village of Thiensville is hereby created to read as follows.

Section 78-55. Testing of Wells for New Developments.


1. Well and pump installation must meet the requirements of Chapter NR812 of the Wisconsin Administrative Code and a constructor's report is on file with the Department of Natural Resources.

2. This ordinance shall apply to wells intended to supply new public water systems as defined in Chapter 811.01(21) (i.e. serving at least 15 service connections or regularly serving at least 25 individuals daily at least sixty days out of the year), or wells intended to supply commercial, industrial, or irrigation uses.

3. The developer shall supply an inventory of wells within a radius of 1,000 feet of the proposed development as provided by state well construction reports showing the depth and water levels of existing wells. General aquifer characteristics should be defined by presenting a map of the existing water table and identification of the geologic unit(s) supplying water.

4. The developer of all wells covered by this ordinance is required to conduct a pumping test at the design capacity of the production well. The pumping test shall be conducted with a test well or production well at the exact location of the permanent well and open to the same stratigraphic material as the permanent well. The well should be pumped at a constant rate for a minimum test duration of 12 hours while water levels are measured in the production well and in a minimum of three surrounding private wells open to the same aquifer. The minimum rate shall be measured at least on an hourly basis and shall be held constant within +/- 10% for the duration of the test.

5. The drawdown data shall be collected in a manner that will allow the transmissivity, storage coefficient, and anisotropy conditions of the aquifer to be determined from the pump test data. This will be accomplished by collecting reasonably accurate data to (+/- 0. 1 ft) at logarithmic time intervals and maintaining a constant pumping rate within +/- 10% of the average value. Recovery data shall be collected at the same frequency and level of accuracy for a period of time sufficient to allow the water level in the pumping well to recover at least 80% of the total drawdown.

6. The data shall be used to predict the steady state drawdown caused by future pumpage and must be calculated by a Professional Geologist or a Professional Engineer using standard industry methods. Steady State drawdown shall be predicted in the aquifer within 1,000 feet of the proposed development, and distances greater than 1,000 feet, if significant impacts are expected. The expected mean daily pumpage for steady state conditions and the maximum daily pumpage for 30 days with no recharge shall be used as the basis for projecting drawdown. The analysis shall be presented in a report that includes the location and construction of monitored wells, a description of field procedures, methods of analysis, predicted drawdown, and all pump test data.

7. If the final test well yield at the stabilized pumping rate is not adequate to meet the minimum demand as previously determined, then the developer shall be required to add additional wells as needed to meet the ultimate minimum demand for the entire development. The impact on the aquifer and adjacent wells shall be determined, as the aggregate of an wells needed to achieve the required capacity. Should surrounding wells be negatively impacted, at the developer's expense, he/she shall adjust all surrounding wells to their prior water capacity. Negatively impacted is defined as "any change in water level or water quality that impairs the ability of another parcel of land to use ground water in a similar quantity with a similar water quality in an existing or future well. These impacts include decreases in water levels requiring lowering of a pump or deepening the existing well, turbidity caused by the drilling process, or other changes in the aesthetic or potable quality of the ground water that can be reasonably associated with the new well. These impacts can occur during the initial pumping test, or can be attributable to the well based on projections of future conditions from the data on aquifer properties collected during the test.

The aquifer data shall be used to make projections of future conditions, which are steady-state at average daily pumping conditions and/or 30 days continuous pumpage at the maximum projected daily water demand with no recharge, whichever shows greatest drawdown. These projections shall be used to determine the total impact of the well.

8. All plans and procedures shall be submitted to the Village and be approved by the Village's hydraulic consultant.


The several sections of this ordinance are declared to be severable. If any section or portion thereof shall be declared by a court of competent jurisdiction to be invalid, unlawful or unenforceable, such decision shall apply only to the specific section or portion thereof directly specified in the decision, and shall not affect the validity of any other provisions, sections or portions thereof of the ordinance. The remainder of the ordinance shall remain in full force and effect. Any other ordinances whose terms are in conflict with the provisions of this ordinance are hereby repealed as to those terms that conflict.


EFFECTIVE DATE. This ordinance shall take effect immediately upon passage and posting or publication as provided by law.