Neponset Stormwater Partnership

Watershed Action PlanningPhase II Stormwater Management Planning

August 13, 2015

Paul G. Costello, P.E.Jason Federico

IntroductionPolaris Consultants

Work with Medfield, 1998 to present

Our Multidisciplinary Work

Work with other municipalitiesOne size does not fit allWatersheds share similar traits (i.e. supply and recharge concerns, TMDLs)SCADA and GIS Management tools are critical

“Water does not resist. Water flows…and is not a solid wall, it will not stop you. But water always goes where it wants to go, and nothing in the end can stand against it. Water is patient…and can wear away a stone. Remember that, my child. Remember you are half water. If you can't go through an obstacle, go around it. Water does.”

Margaret Atwood, The Penelopiad

The Hydrologic Cycle

Los Angeles Water Reservoir Evapotranspiration Control

96 Million, 4-inch diameter ”Shade” Balls for a 175-acre water supply reservoir – save 300MGY

Taking a Holistic ApproachTo Stormwater Permitting

Recognizing the Water Cycle ImpactsMedfield SW Management – RechargeMedfield Wastewater – Discharge/RechargeMedfield Water Supply - Withdrawal

Regulatory ComplianceBalancing the competing water needs of the Medfield DPWConsistency with the Town’s Master Plan Goals –“getting the most bang for the buck”

Early RegulationsFederal Clean Water Act of 1972

The right to pure, clean water – sustainable emphasisWater supply treatment impactsNPDES – Wastewater discharge and wetlands protection (stormwater)

1972 Massachusetts Wetlands Protection ActMarch 1986 Mass. Water Management Act1996 Massachusetts Stormwater Management Standards (1997 Handbook)December 1999 EPA Phase II Final Rule and April 2003 General Permit Conditions

Rise of stormwater task forcesRegulatory reviews – consolidated regulationsStormwater system mapping - aerial mapping and GIS tools with focus on Impaired Waters

Application of ScienceWMA Permits & LitigationDevelopment of Total Maximum Daily Load (TMDL) and Source Control

Neponset: Bacteria (May 2002, Amended 2012) - Illicit discharges to storm drains, leaking sewers, failing septic, sewer overflow (0 cfu/100 ml); and non-point stormwater runoff (GeoMean < 126 cfu/100 ml)Charles: Pathogens (January 2007)Charles: Phosphorous (June 2007) Charles: Nutrients (May 2011)

TMDL Implementation Plans (Neponset 2005)Sustainable Water Management Task Force (2010)

MassDEP, MassDCR, MassDFG, Municipal Stakeholders, Watershed Associations and Technical Representatives15 Advisory Committee & 19 Subcommittee Meetings

The New Regulation - S.W.M.I.Nov. 2012 Massachusetts Sustainable Water Management Initiative (S.W.M.I.)

Reduce the level of controversy and litigation surrounding MassDEP water withdrawal permitting decisionsEstablishing a more transparent, predictable, flexible, and science-based systemEstablish a more holistic watershed approach to water management – Watershed Planning

Nov. 2014 Revised Water Management Act Regulations (310 CMR 36.00)

Identification of permit category ( 1 through 3)Credits for mitigation measures retroactive to 2005

Water, Wastewater and Stormwater Related

S.W.M.I. and WMA GoalsDevelopment of a system that classifies ecological health Streamflow criteria that recommend maximum levels of water withdrawals to protect habitatSafe Yield that defines the maximum dependable withdrawal that can be withdrawn during droughtRecognize the impacts of sewer and stormwater on available water volume

Major S.W.M.I. ElementsDefinition of Safe Yield

Safe Yield establishes the maximum amount of water withdrawal that can be allowed at a major basin. The Safe Yield is calculated as 55% of the Drought Basin Yield plus Reservoir Storage Volumes.

Seasonal Streamflow CriteriaStreamflow criteria will guide WMA permitting decisions seasonally and at a sub-basin scale so as to maintain the magnitude and timing of the natural flow regime.

Baseline Condition The baseline is a reference point against which a request to withdraw groundwater will be compared to determine whether the request represents an increase in withdrawals from the basin. The new baseline is the higher of 2003-2005 average use plus an additional 5%, or 2005 use, plus an additional 5%.

Groundwater Withdrawal Levels and Associated Impacts to August Median Streamflows

Groundwater Withdrawal Levels (GWLs)

Range of Alteration of Unimpacted August Median Flows due to

Groundwater Withdrawal

1 0 < 3%

2 3 < 10%

3 10 < 25

4 25% < 55

5 Greater than 55%

Groundwater Withdrawal Categories

S.W.M.I./WMA Permitting TiersTier 1-

No Additional groundwater withdrawal request above baseline and no change in Groundwater Withdrawal Level or Biological Category

Tier 2 –Additional groundwater withdrawal request above baseline and no change in Groundwater Withdrawal Level or Biological Category

Tier 3 –Additional groundwater withdrawal request above baseline AND change in Groundwater Withdrawal Level and/or Biological Category

S.W.M.I./WMA Offset Mitigation Categories

1. In-streamflow improvement2. Habitat improvement3. Wastewater improvement4. Stormwater/impervious cover5. Water supply management6. Water demand management

Phase II and S.W.M.I. ImpactsRecognition of the new “scientific” Water Volume AND Water Quality IssuesGreater emphasis on flow monitoring and systems maintenance - SCADAStormwater and Sewer Mitigation Measures required under Phase II are Allowable WMA Credits (retro to 2005)

Infiltration and Inflow Credits – Phase II IDDEWastewater Discharge Credit – WWTP NPDESStormwater Recharge Credit – Phase II Issue

Multidisciplinary Approach is needed –Watershed Action Planning

Groundwater Category (GWC) Map

The GWC layer is color-coded to reflect five categories of percent of unimpacted August median flowalteration. This is the percent of August flow represented by August groundwater withdrawals. The ranges forthe percent of flow alteration are: 1 (0-3%) – Light Blue; 2 (3-10%); 3 (10-25%); 4 (25-55%) - Pink; 5 (>55%) - Red. Data revised 2013.

Watershed Protection PlanningUnderstanding local Master Planning and Open Space goals – Land Purchasing NeedsKnowing the local water supply needs – currently and into the futureUnderstanding Watershed Association goals and objectivesReviewing historic studies and TMDLsUsing the NSWP Tool Box (SWPPP, IDDEP, PEOP, Model Bylaws, Water Monitoring Plan)GIS mapping of subwatersheds (NSWP/MAPC)Identifying the “impaired” and critical water bodiesWater Balancing as a tool to address impaired & critical waters – SCADA can help

Supervisory Control and Data Acquisition

Charles River Flow & Rain

Charles River Impacts on WWTP

Inflow ControlManhole Extensions

I/I Control - Manhole Sealing

Infiltration ControlCured-in-place Pipe Lining

WWTP UpgradesReplacement of Waste Activated Sludge (WAS) transfer & displacement pumpsInstallation of chemical flow pacing, pumping, influent pump pacing, and dissolved oxygen sensor SCADA controlsMaintenance of pump chamber and trough Replacement of filter sand mediaReplacement of headworksNew laboratory equipment

Medfield WWTP Sludge Thickener

Charles River Algae Concerns

Excess nutrients like phosphorus and nitrogen, combined with warm temperatures, and sunlight encourage algae growth.

Secondary Clarifier Algae Growth

Secondary Clarifier Covers

Secondary Clarifier Covers

Stormwater Mitigation CostsEstimated Direct Town Management CostHighway Department Culvert Improvements ($825,000)First-Flush Recharge (MHD/Cultec) Improvements ($600,000)Permitting @ $25K/year ($425,000 since 1999)

Stormwater Management Plan (2002)Consolidated Stormwater Regulations(By-law Change Scheduled for 2016)

Drainage Connectivity Mapping (PeopleGIS)Watershed Protection Plan (2014)

Stream Gauge Installation & Monitoring ($10,000)

Since 2005 - $1,710,000

Sewer Mitigation CostsI/I Investigations ($50,000/year)Wastewater Mitigation Investment

36-inch Diameter Charles River Sewer Main Repair ($1,200,000 thru CWSRF program).4,500 Lin. Feet of Pipe Lining ($252,800)WWTP Improvements

WWTP Upgrades ($115,000)Secondary Clarifier Algae Control ($200,000)

Since 2005 - $2,317,800

Land Protection Transfer

$1.4M - 31 Acres Red Gate Farm (Neponset)$0.5M - 47 Acres @ State Hospital with Water Rights (Charles)$0.6M - 4 Acres off Harding Street (Charles)$3.0M – Saw Mill Brook (Charles)

Since 2005 - $5,500,000

FY2016 Budget$125K - Continue I/I Investigations & Drainage Work$29K – Stormwater Permitting

Work with NRWA and MAPCContinue with Drainage System Connectivity Mapping and linkage to PeopleGIS (via PeopleForms)Identify the subwatershed boundaries and characteristics (i.e. Mill and Mine Brooks)Preliminary assessment of water balance and recharge opportunitiesTrack the Draft General Permit

T.B.D. - Stormwater Bylaw in Spring 2016

Medfield GISMapping Summary

2002 Aerial Mapping299,432 feet (56.71 miles) of Sewer Pipe437,658 feet (82.89 miles) of Water Pipe Testing of Outfalls in Critical Areas (167 outfalls) –39% of TownAdditional Outfalls (260 outfalls) Town-wide Drainage Connectivity

427 Outfalls2,268 Catch Basin1,153 Drain Manholes2,849 Pipes and Culverts

PeopleGIS