NEW Water Inflow and Infiltration Unit Distribution Process. February 3, 2015

Transcription

1 NEW Water Inflow and Infiltration Unit Distribution Process February 3, 2015

2 Meeting Agenda What is the NEW Water Inflow and Infiltration (I/I) charge? NEW Water s I/I Distribution process Host Customers Allocation of I/I Units Financial impact Arcadis Billing Methodology Project I/I Distribution Survey NEW Water s I/I distribution feasibility review Future Administration of I/I Distribution

3 NEW Water I/I Charge

4 Current I/I Distribution Process Implemented in the 1970s at the request of the City of Green Bay. Approved by Commission and contained in the Sewer Use Ordinance. Theoretic estimated quantity of I/I based on the pipe age, diameter and length. Assigned I/I leakage rate. 700 gallons per inch-diameter mile/day for pipes > 20 years 200 gallons per inch-diameter mile/day for pipes < 20 years 0 gallons for force mains Host customer credits: Green Bay, Howard, Hobart, Bayshore Sanitary District and Dyckesville Sanitary District. Customers are allocated a proportionate share of NEW Water I/I based upon their previous year s percent contribution of the Green Bay Facility total volume.

5 Current Distribution Process Cont. Theoretic estimated quantity changes when: Pipe age becomes > 20 years - requires tracking of interceptor age New interceptors are installed Rehabilitation/relay projects change the pipe age, diameter or length 2014 theoretic estimated I/I volume was 896,386 gallons per day. 896,386 gallons/day is subtracted from Green Bay Facility Influent (after load assignment) and distributed to customer based upon percent contribution from previous year. 896,386 gallons/1,000 gallon units x 365 days = 327,181 (1,000 gals) annual I/I units. 327,181 (1,000 gallons) x $ per 1,000 gallons = $249,747 annually I/I revenue.

6 Arcadis Billing Methodology Project 0.86% of NEW Water s total user fee revenue ($249,747/$29,172,924). I/I distribution is currently only distributed in the Green Bay Facility drainage basin. Surveys were sent to 15 peer communities. Seven communities responded. Only one community allocates system I/I similar to NEW Water. Based upon a fixed leakage factor of 400 gallons. Stakeholder Advisory Group agreed a fixed leakage factor may be more appropriate.

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8 Feasibility Review Summary NEW Water I/I distribution is not widely understood, easily communicated and is burdensome to administer. Continuing the I/I distribution process would require inclusion of the De Pere Facility interceptors, more host customers and increase NEW Water administrative burden. One Billing Methodology Project goal and criterion was Institutional Acceptance: methodology is easily understood - simpler is better. Changing the I/I leakage rate to 400 gallons would decrease the theoretic estimated daily volume, host customer credits and I/I unit charges: 259,734 (1,000 gallons) units or $198,263 annually. Old NEW Water interceptors are scheduled for rehabilitation within the next five years. As a result, the leakage rates under the current methodology would change from 700 gallons to 200 gallons.

9 Summary Cont. Interceptor segment leakage rates that (due to pipe age) move from 200 to 700 gallons create unrealistic monthly flow units for some credited customers. The I/I distribution process accounts for less than 1% of NEW Water s budgeted revenue. Continuing the process would require significant budget dollars to be designed into the new customer billing program. NEW Water s interceptor system benefits all customers due to economy of scale. NEW Water staff recommends eliminating I/I distribution effective 01/01/2016.

10 Questions Brian Vander Loop, Field Services Manager (920)