Drinking Water Resources Discussion Point Paper

Part I: Introduction

Pipeline safety laws (49 U.S.C. Section 60109) require the Secretary of Transportation to prescribe regulations that establish criteria for identifying each hazardous liquid pipeline facility and gathering line, whether otherwise subject to 49 U.S.C. Chapter 601, located in an area that the Secretary, in consultation with the Environmental Protection Agency (EPA), describes as unusually sensitive to environmental damage if there is a hazardous liquid pipeline accident.

In order to identify unusually sensitive areas (USAs), the Department of Transportation's Pipeline and Hazardous Materials Safety Administration (PHMSA) is seeking information to define a process for USA identification. USAs are expected to be identified with respects to drinking water resources, ecological resources, cultural resources, and Indian Tribal concerns. Development of the USA identification process is iterative, involving both technical and public review workshops. Representatives from the public and private sectors participate on a routine basis at USA identification process review workshops.

Part II: Objective

OPS is considering a "strawman" process that identifies USAs for drinking water resources. The process used for identifying drinking water USAs will employ the general USA identification process (figure 1) that was discussed at the 1/18/96 USA workshop. From figure 1 it can be noted that USAs are identified through a multi-step process, involving the identification of:

1. Environmentally Sensitive Areas (ESAs),
2. USA Candidates/Primary Concerns, and
3. Filtering Criteria.

In order to meet the aforementioned objective, this paper will identify ESAs, USA candidates and filtering criteria as they pertain to drinking water resources.

Part III: Environmentally Sensitive Areas: Drinking Water Resources

Drinking water ESAs may be described by the criteria for drinking water resources discussed in the April 10-11, 1996, USA workshop:

Drinking Water Resources - Surface water intakes and groundwater based drinking water supplies.

Part IV: USA Candidates/Primary Concerns: Drinking Water Resources

USA candidates/primary concerns are a subset of the drinking water ESAs identified in Part III of this document. Drinking water USA Candidates/Primary Concerns include the following:

1. Public Water System (PWS): provides piped water for human consumption to at least 15 service connections or serves an average of at least 25 people for at least 60 days each year. These systems include the sources of the water supplies - i.e., surface or ground. PWSs can be community, nontransient noncommunity, or transient noncommunity systems:
   1. Community Water System (CWS): a PWS that provides water to the same population year round.
   2. Nontransient Noncommunity Water System (NTNCWS): a PWS that regularly serves at least 25 of the same people at least six months of the year. [Examples of these systems include schools, factories, and hospitals that have their own water supplies.]
   3. Transient Noncommunity Water System (TNCWS): a PWS that caters to transitory customers in nonresidential areas (e.g., campgrounds, motels, and gas stations).
2. Wellhead Protection Area (WHPA): the surface and subsurface area surrounding a well or well field that supplies a public water system through which contaminants are likely to pass and eventually reach the water well or well field.
3. Sole Source Aquifer (SSA): areas designated by the U.S. Environmental Protection Agency under the Sole Source Aquifer program as the "sole or principal" source of drinking water for an area.

Part V. Filtering Criteria: Drinking Water Resources

When applied to the USA candidates/primary concerns identified in part IV of this document, the set of filtering criteria shown below may be used to determine which of the USA candidates are USAs with respect to drinking water resources.

Filter Criteria #1: If the public water system is a Transient Noncommunity Water System (TNCWS), the water intakes shall not be designated as USAs.

Filter Criteria #1 Issue: The readily available data source which would be used to make this determination on a nationwide basis is the Federal Reporting Data System (FRDS), that is being replaced by the Safe Drinking Water Information System (SDWIS). There are concerns about the quality of this database and whether it can be used to confidently identify TNCWSs.

Filter Criteria #2: For CWS and NTNCWS that obtain their water supply primarily from surface water sources, and do not have an adequate alternative source of water, the water intakes shall be designated as USAs.

Filter Criteria #2 Issues:

1. A definition is needed for an adequate alternative source of water. The intent is that, in the event of a spill which threatens to shut down a water intake, there would be surface water intakes in a different surface water body which is not in the threat zone, or there would be groundwater sources that could be utilized during the threat period, or there would be other drinking water systems that could temporarily provide drinking water to the shut-down system.
2. There are no readily available, national databases on which this filtering criteria could be applied.

Filter Criteria #3: For CWS and NTNCWS that obtain their water supply primarily from ground- water sources, where the source aquifer is identified as a Class I or Class IIa (as identified in Pettyjohn et al., 1991; EPA Document: EPA/600/2-91/043, August 1991; see Attachment A), and do not have an adequate alternative source of water, the WHPAs for such systems shall be designated as USAs.

Filter Criteria #3 Issues:

1. Determination of the source aquifer is a complex problem, and no national database is available. Furthermore, for some CWS and NTNCWS, the depth of the wells or source aquifer is not known.
2. Seven states do not have Well Head Protection Programs. Where WHPAs are not adequately delineated, WHPA (criteria, threshold, methods, etc.) will be generated.
3. A definition is needed for an adequate alternative source of water for groundwater systems.
4. The classification system discussed in Filter Criteria #3 (above) has data coverage for the conterminous United States. Data for Alaska, Hawaii, and all other U.S. possessions must be identified.

Filter Criteria #4: For CWS and NTNCWS that obtain their water supply primarily from ground- water sources, where the source aquifer is identified as a Class IIb, Class IIc or Class U (as identified in Pettyjohn et al., 1991; EPA Document: EPA/600/2-91/043, August 1991; see Attachment A), the public water systems that rely on these aquifers shall not be designated as USAs.

Filter Criteria #5: For CWS and NTNCWS that obtain their water supply primarily from ground water sources, where the source aquifer is identified as a Class I or Class IIa (as identified in Pettyjohn et al., 1991; EPA Document: EPA/600/2-91/043, August 1991; see Attachment A), and the aquifer is designated as a sole source aquifer, an area twice the WHPA shall be designated as an USA.

Part VI: Recommended Data Source

EPA/600/2-91/043. Regional Assessment of Aquifer Vulnerability and Sensitivity in the Conterminous United States. Office of Research and Development. Washington, DC. 319pp.

Others to be determined.

ATTACHMENT A:

Portions of Regional Assessment of Aquifer Vulnerability and Sensitivity in the Conterminous United States