© 2010 Malcolm Pirnie, Inc. All Rights Reserved

National Implications of the Federal Pollution Limits for the Chesapeake Bay Clean-Up

Clifton Bell, P.E., P.G.

Malcolm Pirnie, Inc.

757-873-4465

cbell@pirnie.com

Challenges for Localities:Address Existing Nutrient Sources

UrbanStormwater

Wastewater WWTP Upgrades Failing septic systems

Stormwater retrofits Fertilizer controls

NewDevelopment

& Redevelopment

Wastewater

Challenges for Localities:Staying Under the Nutrient Cap

Strict stormwater controls

Advanced septic systems

Reuse / recycle Trading/offsets? Septic sprawl?

Urban Runoff: Minority of the Problem, But a Majority of Projected Cost

70% ofTMDLcosts?

Urban Retrofits the Most Expensive Way to Reduce Nutrient Loads

AgriculturalPractices

WWTPUpgrades

UrbanStormwater

Retrofits

$5 - $150per lb phos.

$15 - $200per lb phos.

$3,000 - $20,000per lb phos.

Stormwater Retrofit Costs

Pond retrofits: $15-30k / impervious acre

Advanced retrofits: $75-300k / impervious acre

What regulators have asked:

Retrofit up to 20% of impervious surface in a single MS4 permit term (5 years).

Some Recommendations

Negotiate reasonable MS4 permits• Avoid extensive urban

retrofits

• Emphasize redevelopment-driven improvements

• Non-structural practices

Cross-sector planning Explore opportunities for

wastewater recycle & reuse

Storm-water

Agri-culture

Waste-water