Presentation on theme: "1 Water and Wastewater System Information. 2 PWCSA Water Purchase Key Points From April 21, 2008 Meeting With PWCSA PWCSA is willing to re-open discussions."— Presentation transcript:
2 PWCSA Water Purchase Key Points From April 21, 2008 Meeting With PWCSA PWCSA is willing to re-open discussions on the take- over option Agreement for purchase will not have a take-or-pay clause – Reduces purchase and operational complexity Storage capacity available from PWCSA is only 0.5 MGD – Will not meet DEQ storage requirements for1.83 MGD (in 5 years) – If storage was available as required, it would add an additional $750,000 to $1,000,000 to the purchase agreement
3 General Water Operation Design Criteria Provide fire flow and pressure as demanded Ensure Manassas water and PWCSA water pressures do not conflict on the east side Provide required storage for capacity, now and future Replace wells on the west side Ensure required “turn-over” of the Joshua Court tank (if the City keeps the tank as staff recommend)
4 How the City’s Water System Works Now East and west side systems are separated West side – Served by wells – Emergency backup from Rugby Vault – Water storage in Mathis and Blooms Quarry Tanks East Side – Served with City of Manassas water – Emergency backup from Conner and Roseberry Vaults – Water Storage in Joshua Court Tank
5 Near Term Operation Ensure adequate fire flow to Cougar Elementary and Downtown Center immediately – Pressure sensors at Roseberry Vault and Conner Vault for Cougar Elementary and Birmingham Green are in place Pressure drop occurs when there’s a sudden and/or sustained demand for high flow in the system (fire fighters drawing from hydrants) Pressure sensor senses drop in pressure on City’s side of the Roseberry and/or Conner vault(s) and sends a signal to the Blooms Quarry Fire Booster Station and the pumps kick on Test of the system being scheduled.
6 Interim Operation With PWCSA Water By September 2008 (when agreement is executed) Take 1.33 MGD of PWCSA Water at the Rugby Vault on the west side of the City – Provides PWCSA service to the West side (0.5 – 0.8 MGD) and wells are shut down Fill Mathis and Blooms Quarry tanks with PWCSA water entering from the Rugby vault Create two pressure zones on the east side until final infrastructure is put in place – Eliminates pressure conflict between Manassas water and PWCSA water. – Isolation with existing valves.
7 Interim Operation With PWCSA Water (Con’t) Pump water from the Blooms Quarry tank to the Joshua Court tank using the City’s existing booster station on Blooms Quarry tank site Set Joshua Court tank at level to provide 457 pressure to Cougar Elementary, Downtown Center, and areas adjacent This configuration is temporary until final infrastructure is in place.
8 West side – Construct “Mathis Vault” to serve west side from Manassas – Water storage in Mathis and Blooms Quarry Tanks – Emergency backup from Rugby Vault East Side – Served by PWCSA at Conner Vault and Joshua Court Tank – Emergency backup from the Euclid and Roseberry Vaults – Construct booster station at Joshua Court Tank for maximum effective storage – Water storage in the Blooms Quarry and Joshua Court tanks. Future Operation With PWCSA Water January 2009 Separate east and west side systems again
9 Staff Recommendations Staff recommends that the City keep the Joshua Court tank – Provides control of the City’s water storage needs – Provides much more operational flexibility for regulating flow and pressure on the east side Propose to add infrastructure (engineering estimate being prepared) – Construction of “Mathis Vault” – Construction of booster pump station at Joshua Court Tank – Funding is available in the approved FY08 Enterprise Fund budget
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