250 R.I. Code R. 250-RICR-150-05-3.16

Current through November 7, 2024

Section 250-RICR-150-05-3.16 - Wellhead Protection

A. Delineation of Wellhead Protection Areas

1. Wellhead protection areas for each public well in Rhode Island approved by the Rhode Island Department of Health shall be established by the Department of Environmental Management. A DEM approved wellhead protection area will be effective at the time of the well's approval by the Rhode Island Department of Health. See § 3.24 of this Part for a statewide map showing wellhead protection areas. Wellhead protection areas can be viewed in greater detail on the DEM website at www.dem.ri.gov. Wellhead protection areas are delineated in accordance with the following:

a. The wellhead protection area for community and non-transient non community water supply wells completed in stratified drift will be determined by DEM review of hydrogeologic models submitted by a well owner. If such delineation is not available at the time of the well's approval by the Department of Health, an interim wellhead protection area shall be designated as a 2000 foot radius circle, until such time that a delineation is accepted by the Department of Environmental Management.

b. The wellhead protection area for wells completed in bedrock (community and non-community water supply wells) is a calculated fixed radius based on the Rhode Island Department of Health approved pump rate with a minimum radius of 1750 feet. See § 3.16(A)(1)(b)(1) of this Part for a list of pump rates and corresponding wellhead protection area radii. For pumping rates not provided in § 3.16(A)(1)(b)(1) of this Part, the wellhead protection area radius shall be calculated using the formula below in § 3.16(A)(1)(b)(2) of this Part.

(1) Wellhead Protection Area Radius for Bedrock Wells

Pumping Rate (gallons per minute)	Radius (feet)	Pumping Rate (gallons per minute)	Radius (feet)
[GREATER THAN AND EQUALS TO]10	1750	23	2411
11	1820	24	2440
12	1872	25	2466
13	1920	30	2568
14	1965	35	2638
15	2008	40	2689
16	2087	45	2729
17	2153	50	2760
18	2211	60	2806
19	2261	70	2875
20	2305	80	2985
21	2344	90	3068
22	2380	100	3133

(2) Where: s = drawdown (1 foot); Q = well pumping rate; T = transmissivity (374 gallons per day per ft); S = storage coefficient (.01 (dimensionless)); t = time (200 days); W(u) = well function (dimensionless); and r = distance from pumped well. 114.6 and 1.87 are coefficients generated for conversion from metric to English units and conducting some simplifying calculations.

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c. The wellhead protection area for any other groundwater source used as a public water system, including springs, wells completed in till deposits, transient non-community water supply wells completed in stratified drift, and any well where the geologic formation supplying the water is unknown, will be a radius of 1750 feet.

2. Wellhead protection areas in Rhode Island include those portions of wellhead protection areas for public wells in Connecticut and Massachusetts that extend into Rhode Island as a result of delineations done in accordance with Connecticut or Massachusetts state environmental or health department requirements or policies.

3. If the boundary of a wellhead protection area established by the Department is in dispute, the burden of proof shall be on the person disputing the boundary to show to the satisfaction of the Department a more accurate delineation. If the wellhead protection area in question is for a community water supply well, the procedure in § 3.10 of this Part for Modification of Groundwater Classification must be followed.

B. Refined Wellhead Protection Areas: The Department, water suppliers, or other state or federal agencies may delineate refined wellhead protection areas, which are prepared using more complex methods or additional data than that used in the initial or most recent delineation. Requests for Department approval of refined delineations shall follow the procedure below:

1. Requests for approval of refined wellhead protection areas shall include, at minimum:

a. A map of the well location and proposed refined wellhead protection area using the United States Geological Survey 7.5 minute quadrangle map (scale of 1:24000);

b. Detailed description of the mapping methodology;

c. List of data sources;

d. Detailed description of field methods and results for such activities as pump tests and water table measurements;

e. Detailed description of modelling method, assumptions, results, and principal model input and output values; and

f. Water table map used in the refined wellhead protection area mapping;

2. Additional information may be required by the Director in order to adequately review a proposed refined wellhead protection area.

3. If approved, the refined wellhead protection area delineation shall supersede the initial or most recent wellhead protection area delineation.

C. Deletion of Wellhead Protection Areas: A public well and its wellhead protection area delineation will be deleted from the Department's Wellhead Protection Area map and no longer subject to provisions of these rules when the Rhode Island Department of Health has determined that the well is no longer an approved public drinking water supply and the Director has determined that maintaining the wellhead protection area no longer serves the public interest.

D. Addition of Wellhead Protection Areas: A public well and its wellhead protection area delineation will be added to the Department's Wellhead Protection Area map and subject to the provisions of these Rules at the time of approval by the Rhode Island Department of Health as a public drinking water supply or if the Director has determined that it serves the public interest to add a wellhead protection area for a well site not yet approved by the Department of Health, but which will likely be used for public drinking water supply in the future.

250 R.I. Code R. 250-RICR-150-05-3.16

Adopted effective 1/9/2019
Amended effective 12/28/2023