Multi-Jurisdictional-Use Facilities Capital Cost Allocation Study Update Presented to Blue Plains Regional Committee December 20, 2010 District of Columbia Water and Sewer Authority

Agenda 1.Review allocation method 2.Proposed changes to method 3.Other discussion items

Review- Purpose  To develop a method to allocate capital costs for sewer multi-jurisdictional use facilities (MJUF) inside the District among all multi-jurisdictional facility users Includes identifying all MJUF, some were not previously recognized Method would proportion costs to the demands each user is capable of placing on the capacity of the facilities

GRAVITY SEWERS User shares of capital costs for a multi-jurisdictional sewer are proportional to the calculated peak flow attributable to each particular user PUMPING STATIONS Suburban users’ share of capital costs is proportional to the ratio of their calculated peak inflow at a pumping station to its rated firm pumping capacity Ratio of remaining pumping station firm capacity to the total rated firm pumping capacity represents the District’s share of capital costs FORCE MAINS Users’ capital cost shares are in the same ratio as their cost shares at the connecting upstream pumping station, adjusted for any additional District inputs en-route REVIEW- Recommended Allocation Method (IN ACCORDANCE WITH IMA COST ALLOCATION PRINCIPLES)

REVIEW- Hydraulic Model Methodology  Uses the MIKE URBAN model to replicate conditions under realistic peak demands  Suburban flow allocations equal to the IMA peak flow allocations as they are the maximum capacity required to be routed along multi- jurisdictional facilities  District peak flows are added along the multi-jurisdictional sanitary and combined sewer routes  In District multi-jurisdictional sanitary sewers include peak hourly sanitary flows, base groundwater, I/I, and private property stormwater allowances which are added to suburban peak flows  In District multi-jurisdictional combined sewers include stormwater runoff from the 15-year design storm added to peak hourly sanitary flow, groundwater and I/I allowances, and suburban peak flows

Current Study Constraints  Develop a capital cost allocation method compliant with existing legal structures: DC Water’s enabling legislation Blue Plains Intermunicipal Agreement (IMA) Anacostia Force Main Agreements Potomac Interceptor Agreements Accepted funding cost sharing for: o Potomac Pump Station o Rock Creek Pump Station  Four (4) previously unrecognized multi-jurisdictional sewers and three (3) pumping stations were identified within the District

REVIEW- Sewer MJUF Implications to CIP  Current 10 year CIP Projects with identified MJUF = $395M  Future CIP Projects to be added from Facilities Plan with identified MJUF = $144M  Summary does not include SLRP projects (locations prioritized based on site rankings; locations not identified until Design start)

REVIEW- Current CIP w/ Multi-Jurisdictional Analysis $ M Total CIP Projects w/ Multi-Jurisdictional Use $ 87.2 M Projects w/ Prior Agreements $ 2.7 M Construction Completed $ 56.0 M BPIS Rehabilitation Project $ 72.4 M Other Projects In Construction $ M Projects in Planning or Design

Proposed Changes 1.Expand proposed MJUF cost allocation method to include the Potomac Interceptor. 2.Current projects that alter suburban flow routes of MJUF to show proposed revisions not the current configuration. 3.There are several locations along DC / MD border where District flow leaves DC and enters WSSC before ultimately ending back in DC. This needs to be accounted for in the District capital allocation. 4.There are several locations along DC / MD border where WSSC flow enters the District but not at the onset of the major highlighted routes. This needs to be accounted for in the suburban capital allocation All legal agreements except DC Water’s enabling legislation and current IMA should be eliminated as an artificial constraint to the methodology

Proposed Change #1 Expand MJUF for the PI 1. Expand proposed MJUF cost allocation method to include the Potomac Interceptor. Capital costs for the PI would be proportionate to the IMA allocation for each user. Projects for the PI would have a job specific cost split based on flow use at the specific location.

Proposed Change #2 Show Future Configuration 2. MJUF affected by current CIP projects to show proposed revisions not the current configurations Therefore, cost allocation would be allocated to the user(s) receiving the benefit of the project Affects Route 2 – Upper Potomac Interceptor o Current project (G401)

Proposed Change # 3 Account DC flow to WSSC 3.There are several locations along DC / MD border where District flow leaves DC and enters WSSC before ultimately ending back in DC. This needs to be accounted for in the District capital allocation. Flow leaving DC to WSSC re-enters DC at the start of some of the MJUF Thus, reduces suburban percentage of flow at onset of each affected route

Proposed Change #4 Account WSSC flow to DC 4.There are several locations along DC / MD border where WSSC flow enters the District but not at the onset of the major highlighted routes. This needs to be accounted for in the suburban capital allocation. Fraction of flow but small collection system routes contribute to identified MJUFs Suburban flow volumes and percentages for MJUF may increase slightly but not at the start of the routes Collection system sewers proposed to be included as MJUF for capital costs

Proposed Change #5 Avoid legal constraints 5. All legal agreements except DC Water’s enabling legislation and current IMA should be eliminated as an artificial constraint to the methodology Current cost allocations / agreements for Potomac Pump Station and Rock Creek Pump Station were based on the best available information at the time, but they are not consistent with the model and findings. Proposed to use hydraulic model in lieu of prior agreements.

Discussion Item #1 IMA Rent 1. WSSC currently pays O&M costs and rent on the Upper PI, Rock Creek Main Interceptor, Anacostia Main Interceptor and Outfall Sewer System (see Section 6.G.1 of the IMA). Should WSSC pay capital costs on these facilities in addition to the rent and O&M?

Discussion Item #2 Framework not Agreement 2. Report should be considered a tool / reference for the BPRC Engineers. Report in and of itself can not be considered “agreement of the Engineers” (see Section 6.B.1 of the IMA). The IMA says that the “Engineers” need to agree on the “need, location, size, allocation of capacity, and allocation of cost” prior construction. This document is a tool to facilitate this as the framework, but there still needs to be a more defined process for each project that addresses all of these aspects.

Discussion Item #3 Flow Attenuation 3. Suburban users opine that the methodology does not seem to account for any attenuation of Suburban flow as it passes through the DC system. “It appears the model routing attenuates the total peak flow, but the Suburban percentage is calculated as the sum of the Suburban peak flows at the boundary divided by the attenuated total peak flow, thus increasing the suburban proportionate share in the downstream direction.” Model adds District flow to routes at multiple nodes as route progresses through the District. IMA peak flow added to the District calculated peak flow. Suburban flow decreases proportionately as flow progresses in the downstream direction.

Discussion Item #4 Clarify LTCP Facilities 4. It was difficult to follow how the LTCP was accounted for. Suggest that THIS BE CLARIFIED.