Groundwater Management

Watershed & Water Regs Basics for Municipal OfficialsOctober 27, 2016

Russell Urban-Mead, CPG, LEED® APThe Chazen Companies

Course Outline

• Copious Water • But Local Overuse & Quality

Problems Possible• Groundwater Management –

– A Model Ordinance adopted by Towns

– Under SEQRA by Planning Boards

Copious?!• 38 to 44 inches of precip/year:

– 15 inches in mid-west– Kansas aquifers recharged thousands of

years ago by glaciers– California out of Water– Florida/Georgia/Carolinas droughts

• Hudson River– Dutchess is the Freshwater mouth– Average flow: 9.3 million gals/MINUTE (Po water plant takes just 0.07%)

• Climate Change predicts MORE

Copious?!

Our region could be thought of as the world’s

Saudi Arabia of Water

What Does it Look Like?

Contaminant Sources • Point Sources – manufacturing, gas

stations, spills, dry cleaners.• Non-Point – many associated with

broadly distributed land uses– Road deicers– Septic systems– Sediment– Nutrients (lawns, ag, septics)

Groundwater under Developed Areas..

• Nitrate and hardness rises where septics are used

• Sodium & chloride rises where road density increases, and sometimes locally due to softeners

• Point contaminants by specific use

Local Over Use • Many Straws:

– Wells can compete with each other

– Wells or surface withdrawals can deplete streams or wetlands

• Sprout Creek flow declines• Millerton high pumping can dry

Webutuck Creek headwater

Aquifer Ordinance Developed by 4 Dutchess County Towns, supported by

Dutchess County• 6 months - aquifer characterization• meetings to negotiate viable & technically-

sensible protection levels• legal consultant and hydrogeologist prepared the

first model ordinance.• model has been evolving ever since• the model ordinance has so far been adopted by

Amenia (primary version w/ two zones) and Pleasant Valley (reduced version w/ one zone).

Pleasant Valley Amenia

LaGrangePhilipstown

Gardiner

Aquifer Protection Model Ordinance

• Option 1 – Two zones – Higher protection for intensively used

aquifers (wellhead protection zones, well clusters in hamlets, and some high-capacity aquifer areas)

– Modest protection everywhere else– Needs a map

• Option 2– One zone– Mid-level protection everywhere– Needs no map if adopted for whole town

Development Standards in the Model Ordinance

• Quality:– Various special permit uses, with an application

process and suggested Special Conditions– A limited # of prohibited uses in the 2-zone version– No new buried heating oil tanks under 1,100 gallons – Cluster subdivision guidance

• Aquifer Capacity: – Any project that consumes more groundwater than

is recharged on site is a SEQRA Type I action.– Pumping Test Evaluation Guidance

Cluster Subdivisions• If you plan to use individual wells and septic

systems, limit water quality defects this way:– Multiple small clusters better than one big– Lay out the cluster along a hillside so septic

plumes don’t flow to wells– Modest size parcels (>1 acre) are better than small

parcels (<1 acre).– Extended well casings can help if cluster is near an

aquifer discharge area (lake or river).

Extended casing: in low areas helps to extend well intake below sanitary discharges

High elevation areas benefit less from extended casing

Better Pumping Tests for Reliabilty and Fewer Off-site Impacts

To satisfy SEQRA and Reliability • For Community Water Wellfields

– Monitor existing offsite wells

– Monitor streams and wetlands

– Include a water budget analysis with the pumping tewt report.

– Conduct tests at higher rates if conducted during wet periods (e.g. 15% more if precip is 15% over average during prior 4 months)

Better Pumping Tests• For Major Subdivisions with Individual Wells

– Test 20% of parcels at 5 gpm each, simultaneously for at least 24 hours, using wells predrilled to satisfy DOH

– Monitor streams, wetlands and offsite wells (these conditions may be waived if parcels exceed County

average parcel size recommendations)• For Public Water System Wells (restaurants, schools,

businesses) – Require some of the testing needed

for community water systems (prior slide)

Parcel Sizes and Water budgets:

Hydrologic Soil Groups across the

CountyB and C-C/D soils cover

83 % of County

Figure Source: County Planning

Water Budget

Analyses

Recharge Data are Useful

Example: a 40 acre site in the Wappinger Watershed with 25% HSG B and 75% HSG C would receive

10 acres at 13.3 inch/year = 9,895 gpd 30 acres at 6.8 inch/year = 15,178 gpd

25,073 gpd (17.4 gpm) (SO: a project consuming more than 17.4 gpm might warrant more

SEQRA review of potential wetland, stream or offsite well impacts, or more careful water supply tests)

Water Budgets and

Sustainable Rural Parcel

Sizes

Septic Minimum Density Data are Useful

Example 1: the 40 acre site on prior slide with 25% HSG B and 75% HSG C will sustain (without roads) 10 acres with 1.8 acre/system = 5.6 30 acres with 3.3 acre/system = 9.9

~15 homes

Example 2: Consider where water & sewer may be needed for existing homes

Towns can adopt the Water Resource Lawor Planning Boards can apply its guidance

under SEQRA • Groundwater capacity and quality is protected:

– Quality and Capacity Protection– Cluster Subdivision layout guidance– Better pumping test protocols

• Many Other Issues are directly/indirectly addressed– In-Stream flows are preserved if density guidance is used– Trace Pharmaceuticals in aquifers are diluted – Impacts of climate change are managed by use of careful

standards for pumping tests and density considerations– Wetlands and riparian corridors benefit from density

guidance

Review of this Evening’s Outline

• Copious Water • But Local Overuse & Quality

Problems Possible• Groundwater Management Options:

– A Model Ordinance adopted by Towns

– Approaches to Use also under SEQRA by Planning Boards

Resources and Credit• Many studies and reports are available on

Dutchess County website. http://www.co.dutchess.ny.us/CountyGov/Departments/Planning/16891.htm Much of this analysis was funded by Dutchess County’s Department of Planning and Economic Development.

• Feel free also to contact Russell Urban-Mead at Chazen rum@chazencompanies.com