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Question 4 - Impact on Groundwater - Full EAF (Part 2)

Full Environmental Assessment Form (FEAF) Workbook

The proposed action may result in new or additional use of ground water, or may have the potential to introduce contaminants to ground water or an aquifer. (See Part 1.)

This question asks the reviewing agency to evaluate potential impacts on the use of, and contamination of, groundwater resources. Groundwater is an important natural resource used by industrial, commercial, agricultural, and residential uses for manufacturing, irrigation, and drinking water purposes. About one quarter of New York residents rely on groundwater as a source of potable water. Water is not an inexhaustible resource, and proposed actions need to be evaluated for their potential impact on both the quantity and the quality of the groundwater source they may use or affect. Once a groundwater supply is exhausted or contaminated, it is very expensive, and sometimes impossible, to replace.

To answer this question

Review Part 1 questions D.2.a., D.2.c., D.2.d., D.2.p., D.2.q., and D.2.t.

To begin its evaluation, the reviewing agency should ask "Does the proposed action include any of the following:"

  • Excavation, mining, or dredging during or after construction?
  • A new or additional demand for water?
  • A public, private, or commercial potable water source that will be added or impacted by the proposed project?
  • Generating any liquid waste, including but not limited to wastewater
  • Bulk storage of more than 1,100 gallons of petroleum or chemical products?
  • Use of pesticides, herbicides, or insecticides during or after construction of a commercial, industrial, or recreational use?
  • Commercial generation, treatment, storage, or disposal of hazardous wastes?

If the answer is no to all of these questions, then check 'No' and move on to question 5. If the answer is yes to any of these questions, then check 'Yes' and answer sub-questions (a) through (h).

The sub-questions in this section can be divided into two groups. Sub-questions a, b, and c focus on the quantity aspects of groundwater. Sub-questions d, e, f, and g focus on potential contamination of groundwater.

Identifying potential impacts

The reviewing agency should evaluate the following sub-questions and decide if there will be any impact. If there will be an impact, the reviewing agency must then evaluate the magnitude of that impact, and decide if the impact will be small or moderate to large. This will depend on the overall scale and context of the proposed project as described in the Introduction to Part 2. The reviewing agency should be reasonable when conducting this review.

  • If the proposed project exceeds a numeric threshold in a question, it is presumed to be a moderate to large impact.
  • If the proposed project does not exceed a numeric threshold in a question, the reviewing agency should consider the scale and context of the project in determining if an impact may be small or moderate to large.
  • These sub-questions are not meant to be exhaustive. The reviewing agency should use the "Other impacts:" sub-question to include any additional elements they feel need to be analyzed for potential impacts.

a. The proposed action may require new water supply wells, or create additional demand on supplies from existing water supply wells.

b. Water supply demand from the proposed action may exceed safe and sustainable withdrawal capacity rate of the local supply or aquifer. Cite Source:

Private and public water supplies often use groundwater as a water source. In order to maintain a sustainable system, the amount of water withdrawn from these groundwater sources must be balanced with the amount of water returned to the groundwater source. This is known as groundwater recharge. In evaluating the magnitude of potential impacts regarding sub-questions a. and b., it is critical for the reviewing agency to understand the balance between withdrawal and recharge, and how the proposed project might affect that balance.

If the proposed project will be connecting to an existing public water supply that uses groundwater as a source, the pumping capacity of the groundwater wells should be capable of supplying the quantity of water required for both the new use and all existing uses. If new wells will need to be added to an existing groundwater supply system, the impact of this additional withdrawal on the groundwater supply should be evaluated. If the withdrawn water will not be returned to the same groundwater source after use, that will affect the balance of the system.

If there are no existing groundwater wells on the site, then some research or testing will likely be needed to evaluate the groundwater capacity. The municipality may have done a hydrogeology study as part of a comprehensive plan, or as a standalone planning effort. Such a study may include recommendations about sustainable water withdrawals or housing densities for various locations throughout the municipality. The municipality may have standard requirements for water well testing for major subdivisions which include well pump test specifications.

As also mentioned in Question 3.f., it should be noted that registration per NYSDEC NYCRR Part 601.18 is required for interbasin diversion of water or wastewater of 1,000,000 gallons per day or more. In addition, new or increased interbasin diversion of water or wastewater out of the Great Lakes Basin is prohibited except for limited public water supply projects (per NYCRR Part 601.18(j)). The DEC Division of Water should be contacted if this is a component of the project proposal.

Applicable Part 1 Information

D.1.f., D.2.c., and E.2.l.

Also: any municipal-wide hydrogeologic studies done, or site-specific well tests performed by the applicant or required by the reviewing agency.

See: NYS Department of Health, Drinking Water Regulations, Part 5, Subpart 5-1, Public Water Systems - Appendix 5B and Appendix 5D

Analysis

  • What is the type and size of the use?
    • Does the project make use of groundwater resources, or is it located over or near them.
    • How much water will be used, and for what purpose.
    • What is the capacity of the groundwater source to supply the new or expanded use.
    • Will there be an effect on any existing uses already tapping into the groundwater source.
  • Will the water be supplied by an existing system, or will it require a new source?
  • If an existing source will be used, will the existing infrastructure (wells) be able to handle the additional withdrawal?
  • Is the groundwater source able to supply sufficient capacity for the new or additional demand?
  • Is the additional demand placed upon an existing system within the capacity of that system?
  • What is the extent of the groundwater source?
    • Is this an aquifer that supplies drinking water to multiple other uses?

Will there be an impact?

If the proposed project will not require any new or additional water supply, check 'No or small impact may occur' for both (a) and (b), and move on to question (c).

Small Impact:

Examples of projects that may have small impacts would be:

  • The proposed project does not create a need for new water, or wastewater infrastructure.
  • Proposed projects that will connect to an existing public water supply with adequate capacity, and adequate plans for growth.
  • The intended water supply is a new ground water well, and there are no known problems with adjacent similar uses using the same ground water supply.
Moderate to Large Impact:

Examples of projects that may have moderate to large impacts would be:

  • The water supply demand from the proposed action is expected to exceed the sustainable withdrawal capacity rate of the groundwater source.
  • The proposed project will connect to a public water supply that is near full capacity, or the intended ground water source has known limitations.
  • The proposed project will result in significant drawdown or reduction in flow of a nearby surface water body.

c. The proposed action may allow or result in residential uses in areas without water and sewer services.

Residential development that occurs outside of water districts and sewer districts will most likely depend on individual drilled wells and onsite septic systems. These types of projects need to be evaluated for adequate ground water supply, and recharge of the groundwater supply from wastewater. Some municipalities may have specific testing requirements in place that outline the number of test wells required based on the number of new residential parcels proposed, and specific well pump testing specifications. Absent these requirements, it will be up to the reviewing agency to determine if the information included in the FEAF is adequate to make such a determination. The reviewing agency should look at the information supplied in Part 1 of the FEAF, including soil drainage and depth to water table attributes, and water well data from any existing wells on the site or surrounding area.

Applicable Part 1 Information

D.1.a., D.2.c., and E.2.l.

Analysis

  • What is the type and size of the use?
    • How much water will be used, and for what purpose.
    • What is the capacity of the groundwater source to supply the new or expanded use.
    • Will there be an effect on any existing uses already tapping into the groundwater source.
  • Is the groundwater source able to supply sufficient capacity for the new or additional demand?
  • Is the additional demand placed upon an existing system within the capacity of that system?
  • What is the extent of the groundwater source?
    • Is this an aquifer that supplies drinking water to multiple other uses?
  • What is the location of the use in relation to the groundwater source?
    • Will the water be used in the same location it is being withdrawn from?
    • Will the water be returned to the ground in the form of wastewater?
    • Will it be returned to the same location it was withdrawn from?
  • What other uses depend on the groundwater source?
  • How will the water be disposed of after its use?
    • Will it be disposed of onsite, or off site?
    • What will be the quality of the wastewater be?
  • Has there been any evaluation of the groundwater resources of the area?
  • Are there any well logs or other documentation of surrounding existing groundwater wells?
  • Have there been any pump tests done for existing wells on the property?
  • Are the soils on the site conducive to onsite septic systems? Poorly drained, or excessively drained?

Will there be an impact?

If the proposed action does not include building any residential uses in areas without water and sewer services, answer "no or small impact may occur."

Small Impact:

Examples of projects that may have small impacts would be:

  • The project is located on a parcel with an existing well, and the capacity of the well is known to be sufficient to supply the project.
  • The project is located on a parcel without an existing well, but adjacent properties with similar uses have drilled wells with sufficient capacity, and bedrock geology and soils are similar to the adjacent sites.
  • A test well has been drilled, and capacity has been determined to be adequate for the proposed use.
Moderate to Large Impact:

Examples of projects that may have moderate to large impacts would be:

  • When a hydrogeology study has determined that the area surrounding the proposed project may not have sufficient groundwater or recharge rates to sustain the proposed project.
  • Groundwater resources are highly variable in an area and could be impacted by excessive water withdrawal as determined by examination of well logs or hydrogeology studies. This is of special concern in areas relying on limestone bedrock.
  • When a single large user, or many smaller users such as a residential development, relies on groundwater wells without pump testing to determine water capacity or impacts of withdrawals on existing wells.
  • When soils have severe limitations for development of septic systems due to slope, wetness, shallowness, or poor percolation.
  • Groundwater withdrawal results in significant reduction in storage or flow in a nearby surface water body.

d. The proposed action may include or require wastewater discharged to groundwater.

If the proposed project will involve the use of water, but will not connect to an existing wastewater treatment system, there will likely be some discharge of wastewater to groundwater. The most common example of this is the use of onsite septic systems in residential developments. If this wastewater will be returned to a groundwater source that is also being used for drinking water, careful consideration must be made for potential impacts. If the wastewater will be returned to a different groundwater source than it is being withdrawn from, there may be impacts to the water table.

Applicable Part 1 Information

D.2.d. and E.2.l.

Analysis

  • What is the location of the use in relation to the groundwater source?
    • Will the water be used in the same location it is being withdrawn from?
    • Will the water be returned to the ground in the form of wastewater?
    • Will it be returned to the same location it is withdrawn from?
  • What is the extent of the groundwater source?
    • Aquifers do not follow property boundaries.
  • What other uses depend on the groundwater source?
  • How will the water be disposed of after its use?
    • Will it be disposed of onsite, or off site?
    • What will be the quality of the wastewater be?
  • Will the additional wastewater affect the water table?
  • Can the drainage characteristics of the soils found on the site handle the additional wastewater discharge?

Will there be an impact?

If the proposed action does not include wastewater discharge to groundwater, answer "no or small impact may occur."

Small Impact:

Small impacts could occur when:

  • The county soil survey indicates the soil types found on the proposed project site are conducive to onsite septic systems.
  • The county health department has approved an onsite septic system location.
  • An engineer has designed an onsite septic system in accordance with the requirements of the county health department and the municipalities' requirements.
Moderate to Large Impact:

Examples of projects that may have moderate to large impacts would be:

  • The proposed project will require multiple onsite septic systems.
  • The proposed project is sited in an area having limestone or highly fractured bedrock where there is risk of widespread movement of contaminants.
  • The proposed project will require a community sewage treatment system with a common leach field for multiple residential or commercial uses.

e. The proposed action may result in the construction of water supply wells in locations where groundwater is, or is suspected to be, contaminated.

Operating or closed solid waste facilities, use or disposal of hazardous waste, and history of a spill or accidental contamination on or near the site all pose possible impacts to groundwater, and will affect its potential use as a drinking water or irrigation source.

Applicable Part 1 Information

D.2.c., D.2.p., E.1.f., E.1.g.,E.1.h., and E.2.l.

Analysis

  • What is the type and size of the use?
    • Does the project make use of groundwater resources, or is it located over or near them.
    • How much water will be used, and for what purpose.
    • What is the capacity of the groundwater source to supply the new or expanded use.
    • Will there be an effect on any existing uses already tapping into the groundwater source.
  • What is the location of the use in relation to the groundwater source?
    • Will the water be used in the same location it is being withdrawn from?
    • Will the water be returned to the ground in the form of wastewater?
    • Will it be returned to the same location it was withdrawn from?
  • What is the extent of the groundwater source?
  • What other uses depend on the groundwater source?
  • Is the proposed project located near an operating or closed solid waste management facility, hazardous waste use or disposal site?
  • Is the proposed project located on or near a former agricultural operation with a history of pesticide use?
  • Has there been any testing of the soils on the site, or groundwater near the site?
  • Will the groundwater withdrawal effect nearby surface water bodies?
  • Will water be diverted outside of the Great Lakes basin?

Will there be an impact?

If there are no known possible sources of contamination on the site, or on adjoining sites, answer "no or small impact may occur."

Small Impact:

Small impacts could occur when water supply wells are planned where:

  • A small accidental spill has been recorded on the site, but remediation has removed all traces of contamination.
  • A hydrogeology study has confirmed that the soils, topography, and distance between a proposed new well site and former municipal land fill offer adequate protection to the proposed drinking water source.
Moderate to Large Impact:

Moderate to large impacts could occur when water supply wells are planed where:

  • Groundwater resources are the only source of potable water for an area and it could be impacted by pollution known or suspected to exist in the wellhead area.

f. The proposed action may require the bulk storage of petroleum or chemical products over ground water or an aquifer.

Bulk storage of petroleum or chemical products over groundwater or an aquifer can pose risk and adverse impacts to water quality. This is especially important when land uses in the area rely on those groundwater sources for potable water. Such uses can pose possible impacts to groundwater, and may affect its potential use as a drinking water or irrigation source.

Applicable Part 1 Information

D.2.c., D.2.p., E.1.f., E.1.g.,E.1.h., and E.2.l.

Analysis

  • What is the type and size of the use?
    • How many gallons are proposed to be stored?
    • Will there be frequent dispensing of the fuel or chemical such as in a commercial propane fuel depot or gas station?
  • What is the location of the use in relation to the groundwater or aquifer source?
    • Will the water be used in the same location it is being withdrawn from?
    • Will the water be returned to the ground in the form of wastewater?
    • Will it be returned to the same location it was withdrawn from?
  • What is the extent of the groundwater source?
  • What other uses and how many depend on the groundwater source?
  • What containment design requirements are proposed?

Will there be an impact?

If there is no petroleum or chemical storage proposed, or the proposed project will not include the storage of more than 1,100 gallons of petroleum products, or 550 gallons of chemical products, answer "no or small impact may occur."

Small Impact:

Small impacts could occur when:

  • A hydrogeology study has confirmed that the soils, topography, and distance between a proposed aquifer or groundwater source offers adequate protection to those water sources.
  • A petroleum or chemical storage facility is proposed in an area that uses a municipal water supply system so the risk of contamination to potable water is small.
  • Site layout and spill containment plans are such that even in the event of a spill, the risk to groundwater and aquifers has been determined to be small.
Moderate to Large Impact:

Moderate to large impacts could occur when:

  • The aquifer or groundwater resource is the only source of potable water for residents and businesses and it could be impacted by pollution.
  • A new petroleum storage facility is proposed in a rural residential area without access to a municipal water supply system.

g. The proposed action may involve the commercial application of pesticides within 100 feet of potable drinking water or irrigation sources.

The application of pesticides in close proximity to groundwater drinking water sources opens up the possibility of substantial impacts to human health. Conditions of the site will affect the potential for leaching of pesticides into groundwater. These include: depth to groundwater, geologic conditions, topography, climate, and irrigation practices.

Applicable Part 1 Information

D.2.c., D.2.q., E.2.h., and E.2.l.

Cornell University's Fact Sheet: Pesticides and Groundwater: A Guide for the Pesticide User

Analysis

  • What is the type and size of the use?
    • Does the project make use of groundwater resources, or is it located over or near them.
  • What is the location of the use in relation to the groundwater source?
  • What is the extent of the groundwater source?
  • What other uses depend on the groundwater source?
  • Will the proposed project include the commercial application of pesticides?
  • Is there adequate separation between the soil surface and the water table?
  • Is there adequate separation between the application sites, and any water withdrawal sites?
  • What kind of cleaning, storage, and disposal procedures will be used?
  • Will the proposed project use Integrated Pest Management (IPM) (see D.2.q.)

Will there be an impact?

If the proposed action does not involve the commercial application of pesticides, or if there are no drinking water or irrigation water sources on or within 100 feet of the proposed site, answer "no or small impact may occur."

Small Impact:

Small impacts could occur when:

  • Storage of pesticides, herbicides or other chemicals will take place, but is done in a completely enclosed structure that meets appropriate storage requirements, and the site is greater than 300 feet from any water body, well or water source used for irrigation or drinking.
Moderate to Large Impact:

Moderate to large impacts could occur when:

  • Storage of pesticides, herbicides or other chemicals will take place on a site that is within 100 feet of a water body, well, or surface water source used for irrigation.

h. Other impacts:

There may be other impacts identified by the reviewing agency that are not addressed by the above questions. If so, they should be identified and briefly described here. Some proposed actions may have beneficial impacts on the environment. The reviewing agency can use the 'other' category for that purpose, too.

Examples of 'other impacts' to groundwater:

  • Mining operations may alter hydrology, may place the water table closer to potential contamination, or may change the groundwater recharge rate.

Back to Part 2 (FEAF) Identification of Potential Project Impacts || Continue to Part 2 (FEAF) Question 5 Impact on Flooding


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