A Shortcut to Wellhead Protection Delineation for Some Systems
|Clean, safe drinking water is vital to
your community's health, economy, and future well-being. If the ground water
your community uses becomes contaminated, it may be lost forever as a water
supply, or it may require very expensive treatment to remain usable. The
best way to make sure your water supply remains safe now and for the future
is to protect the area around your wells (the wellhead protection area)
from potential hazards.
This publication describes the fixed radius method to delineate a wellhead protection area, which may be an option for water supply systems which pump, on average, less than 100,000 gallons per day.
What Is Wellhead Protection?
Wellhead protection is a way to protect a water supply
by managing an area around the community's wells to prevent contamination.
A team of concerned community members guides the wellhead protection planning
process. The process involves defining and mapping the wellhead protection
area, inventorying potential sources of contamination, developing a plan
to manage the area, contingency planning for possible contamination, and
educating the public.
How Do You Identify Your Wellhead Protection Area?
The area that is most likely to affect drinking water quality and that therefore requires added protection is known as the "wellhead protection area." Delineation is the process of identifying the size and shape of the wellhead protection area. Delineation is important because it serves to focus the attention of the wellhead protection planning team on activities within the area that are potential contributors to ground water pollution. Potential is the important word here, because Indianaís Wellhead Protection Rule emphasizes prevention rather than remediation of ground water problems. Once the team identifies potentially harmful activities, it can begin developing voluntary best management programs and outreach efforts to educate those living and working within the wellhead protection area on how to safeguard the water supply.
Indiana's Wellhead Protection Rule (327 IAC 8-4.1)
allows some smaller communities to choose between two separate methods
for completing a delineation, depending on how much water they pump each
day and how accurate they wish their delineation to be. The more scientific
and accurate method requires hiring a consultant, a qualified ground water
scientist, to determine the area from which the community will draw water
over a five-year time period. (See "Useful Publications" for a publication
on this topic.) Some smaller communities are able to apply to IDEM to use
a "fixed radius method." Using the fixed radius method provides a shortcut
to delineation when compared to the standard modeled delineation process.
The community public water supply systems that are eligible to use the
fixed radius method may use a circle with a 3000-foot radius around their
community drinking water supply well as a wellhead protection area.
Who Is Allowed to Use the Shortcut Method?
If your water supply system pumps less than 100,000
gallons per day, on average, your wellhead protection planning team may
apply to IDEM for approval to use the fixed radius method for delineating
your wellhead protection area. While this method will save you time and
money in the short term, it is not as accurate as the methods using a computer
model. It may define a larger area to inventory and manage or may fail
to include some parts of the recharge area. Figure 1 is a topographic map
comparing a 3000-foot fixed radius delineation with a modeled delineation
of a wellhead protection area.
How Do You Apply for Permission to Use the Fixed Radius Method?
The first step is to verify whether your water supply system pumps less than 100,000 gallons per day. You may use either pumping records or well capacity data from the well log the driller filed when your well was drilled..
If you do not have the well capacity information
or the five years of pumping data, but you think that your water supply
system pumps less than 100,000 gallons per day, you can contact IDEM directly
(at 1-317-308-3321 or 1-800-451-6027 ext. 308-3321) and discuss the options
for getting permission to use the fixed radius method.
How Do You Get Your Delineation Approved?
After you receive approval to use the fixed radius
method from IDEM, you need to send an application for delineation approval
to IDEM. The application should include a copy of the letter granting approval
to use the method, your well logs, and a map of the area. The following
steps will help guide your local wellhead protection planning team through
the process of sending in the information to get your delineation approved.
If available, obtain well logs of your public water supply wells.
You can obtain well logs from the Indiana Department of Natural Resources by calling 317-232-1106 or toll free, 1-877-WATER 55 (1-877-928-3755), or by sending a letter requesting a copy to the Indiana Department of Natural Resources, Division of Water, 402 West Washington Street, Room W264, Indianapolis, IN 46204. Each written request should include the ownerís name, facility name, the street address, and the section, township, and range location. (All available records are filed by section, township, and range, so be sure this information is included.) Water well records are also now available on the Web at < http://www.state.in.us/dnr/water>.
Not all wells were recorded by the well driller when
they were installed. Only the well logs which were recorded are available.
If the log for your community's well is not available, your team should
turn in a statement to that effect with your other documentation.
Obtain topographic maps of your area.
A listing for several sources of topographic maps
is included at the end of this publication. When ordering topographic maps,
your team should be prepared to describe your location. Providing section,
township, and range information is usually the easiest way to be sure you
will receive the correct map(s). If your area falls at the edge or corner
of a map sheet, you may need more than one sheet to show your area completely.
It is a good idea to order several copies of the maps you need - at least
one as a working map to use when you work on the contaminant source inventory
(another part of the wellhead protection planning process), one to keep
locally with a copy of your wellhead protection plan, and one for the submission
package to IDEM.
Draw a 3000-foot radius circle around the well
Once your team has the topographic map, you can draw
a circle with a radius of 3000 feet (1.5 inches on the map that is scaled
at 1:24,000) with the well at the center of the circle. The area inside
this circle is your wellhead protection area. Figure 1 includes an example
of a circular wellhead protection area.
|Step 4: If there are other significant water withdrawal facilities in the area, your team should indicate their locations on the topographic map. Examples of significant water withdrawal facilities may include industries, agricultural processing operations, large-scale irrigation facilities, or another public water supply system. The Indiana Department of Natural Resources (toll-free at 1-877-WATER-55) can provide information about water wells, including any information on significant water users.|
|Step 5: Submit
application for delineation approval to IDEM. The application is available
on the Web at IDEM web site. (See Indiana Information Contacts listed at
the end of this publication.) Although the application covers the entire
process. IDEM has suggested that you send the delineation section first.
Complete the first page and the top of page four on the application form
for this part of the submission. Three things need to be included in the
initial submission to IDEM.
|Send these three things along with a copy of the wellhead protection plan application to:|
IDEM, Drinking Water Branch
P.O. Box 6015
Indianapolis, IN 46206-6015
|IDEM will respond to your application. However, if the response takes longer than you would prefer, your team should continue working on the remaining parts of your wellhead protection plan. By continuing to work on the plan, initial enthusiasm remains high, and your team makes progress toward the goal of wellhead protection planning.|
Wellhead protection is a multi-step process. Once
the delineation is approved, your team can focus on the task of inventorying
the wellhead protection area for potential sources of contamination. Other
tasks include determining how to manage the wellhead protection area to
reduce the risk of contamination, contingency planning in case of future
contamination, and educating the public about ground water and wellhead
protection. Publications on each of these topics are available now, or
will soon be available from your local Purdue Extension county office.
(See "Useful Publications.")
The following Purdue Extension publications provide information about other aspects of the wellhead protection process.
|All these publications are free. Contact
your local county Purdue Extension office or call 1-888-EXT-INFO to obtain
these or other publications.
The USEPA has an informative publication, "Wellhead
Protection, A Guide for Small Communities," EPA/625/R-93/002 available
free by calling 1-800-490-9198.
Indiana Information Contacts
Sources of Topographic Maps
Topographic maps are available from:
Barbara C. Cooper,
Jane R. Frankenberger,
Figure 1. The shortcut, fixed radius, method of delineation may save time and money in the short term, but it is less accurate and often results in delineating a larger wellhead protection area than a modeled delineation.
Figure 2. A sample of a letter to IDEM requesting
permission to use the fixed radius method of delineation.