Authority to build new 2.4M‑gallon tank; commission grants waivers pending bond documentation

The Murrysville Planning Commission on Sept. 9 recommended approval of SP‑5‑25, a major land development application by the Municipal Authority (MAWC) to construct a 2,400,000‑gallon concrete water storage tank on Lions Run Road, subject to two waivers and receipt of bond documentation.

The new tank would sit adjacent to an existing 5,000,000‑gallon concrete tank on the authority’s roughly 4‑acre property in the RR (rural residential) zone. Authority representatives and the project engineers said the primary purpose is to provide storage while the older tank — constructed around 1980 — is taken out of service for a planned rehabilitation that requires up to three months out of service.

Why it matters: The new tank is intended both to maintain service and fire‑flow capacity when the older tank is offline and to add long‑term storage capacity. Commissioners focused discussion on stormwater conveyance, overflow routing, tree cover and whether the borough’s standard amenities bond requirement could be satisfied by the authority’s construction performance bond.

Project specifics Gibson Thomas Engineering presented plans for a 98‑foot‑diameter concrete tank and an on‑site stormwater pond sized for the project. The project team said the site was originally left open for a future tank and that existing tree cover surrounds the property, with no proposed tree removal in the tank footprint. Contract award documents identify DN Tanks as the tank contractor and a total construction contract value of approximately $3,450,000; the stormwater pond cost was estimated by the applicant at approximately $150,000–$200,000.

Waivers and bonds The applicant requested two waivers: (1) allow the stormwater/detention vegetation and landscape plan to be sealed by the stormwater engineer rather than a landscape architect because the planting is low‑level bioretention species consistent with the Pennsylvania stormwater BMP manual; and (2) allow the borough to accept the MAWC performance bond for the project in lieu of a separate borough amenities bond (the authority provided documentation showing a performance bond for the overall contract). Planning staff said the applicant submitted the requested waivers and related documents and that the commission had the documentation required for review, subject to the applicant providing a copy of the performance bond to the borough.

Stormwater and drainage questions Commissioners asked for clarification on the tank inlet, overflow routing and the capacity of an existing 16‑inch drain line that conveys flow from the site toward Lyons Run. The applicant said the new tank’s roof runoff will be directed to a trench and bioretention pond, and that the overflow/drain line ties into the existing conveyance; the applicants said they would not intentionally drain the tank during storm events and that the new tank’s operations will be controlled via SCADA.

Commission action and conditions A commissioner moved to approve SP‑5‑25 with the two waivers described and with the condition that the applicant provide a copy of the performance bond (to satisfy amenities‑bond requirements). The motion carried by voice vote (ayes). Staff will require the applicants to submit any outstanding contract or bond documentation prior to final plan endorsement.

Next steps Staff said the applicant will provide the performance bond copy and coordinate final plan revisions to explicitly show the overflow/drain connections. The applicant said the PCSM plan and NPDES permit had been submitted and recorded as required.