water resources target nitrogen loads will be achieved flexibility for regional solutions site...

Water Resources

• Target Nitrogen loads will be achieved• Flexibility for regional solutions• Site constraints at Buck Island Site are

adequately conditioned• Flow neutrality outside of economic

growth areas is demonstrated

Yarmouth Major Watersheds

Phase 1 - 418,000Phase 2 - 393,500Phase 3 – 590,000Phase 4 – 723,000Phase 5 – 619,000Total - 2.75 MGD

Regionalization

Barnstable

• Potential sharing of treatment facilities• Regional assessment of R8 Hospital Bogs

site for effluent disposal• Flexibility of Pump stations to

accommodate future regional solutions

Regionalization

Dennis

• MEP indicates nearly 100% of septic nitrogen load to upper-Bass River should be removed

• Mid-Bass River is less nitrogen sensitive• Lower-Bass River appears to have more

assimilative capacity

• Bass River will be addressed in subsequent wastewater Planning effort

Effluent Disposal CapacityBuck Island Site R1

Hydrogeologic Investigation and Groundwater Modeling

• Indicates 0.99 to 1.5 MGD of infiltration capacity

Ave BO Peak• Phase 1 318,000 gpd 418,700• Phase 2 628,000 gpd 812,200 1.0 MGD• Phase 3 1.1 MGD 1.40 MGD 1.8 MGD

• CWMP proposes decreasing 4 ft separation to increase infiltration capacity.

Parkers River Watershed

Effluent Disposal Buck Island Site R1 Nitrogen Constraint

MEP indicates 1.93 MGD at 3 ppm is the nitrogen loading constraint for Parkers River when Culvert is completed

• CWMP Phase 1 and 2 will have lower flows with a limit of 7 ppm that operationally will approach 5 ppm.

• Phase 3 modifications are proposed to achieve a maximum of 5 with an average to approach 3 ppm.

• Additional Effluent Disposal Capacity will be required beyond Phase 3

Interbasin Transfer of Nitrogen

• Phase 1 as modified in the SEIR will have a no-net increase to the Greater Parkers River

Seine Pond• The MEP required septic nitrogen decrease for

the Seine Pond Sub-watershed is 59%• Seine Pond will receive 25% of effluent nitrogen

for an additional 4kg/day at Phase 2• Suggest expediting sewering in Seine Pond

subwatershed from Phase 4 to Phase 1 or 2.

Comprehensive Effluent Disposal

• Effluent Disposal sites in lower and mid Bass River and Nantucket Sound Watersheds have less constraints from nitrogen loading perspective.

• Additional Site investigation is required for future Phase and Bass River Planning effort

Sewer Service Alternatives

Maximize use of R1 site for nitrogen removal

Long Pond• Groundwater flow and natural attenuation

removes approximately 95% of the nitrogen

Plashes Pond• Natural attenuation should be consideredNantucket Sound• No nitrogen limitation

Growth Controls

Yarmouth will be seeking 0% SRF Loan which requires flow-neutral controls

• CWMP uses 16% for buildout + 5 % for additional economic development

• Commission is working with Town to re-evaluate buildout and buildout flows

Conclusion and Conclusion and RecommendationsRecommendations

• Single EIR is sufficiently detailed to Single EIR is sufficiently detailed to complete MEPA/Joint Review processcomplete MEPA/Joint Review process

• Subcommittee vote to approve staff Subcommittee vote to approve staff report as comment letter to MEPAreport as comment letter to MEPA

• Vote to authorize the Subcommittee Vote to authorize the Subcommittee Chair to sign a cover letter Chair to sign a cover letter transmitting the staff report to MEPA transmitting the staff report to MEPA on behalf of the Commissionon behalf of the Commission

• Comment period closes 8/19/11Comment period closes 8/19/11