Client: San Jacinto River Authority (SJRA)
Location: Woodlands, TX
Project is an engineering study to determine the feasibility of consolidating two WW treatment facilities and associated collection systems that serve portions of The Woodlands, Texas. These areas consist primarily of residential developments with little, if any, undeveloped area. Extensive research and data collection was performed for the existing treatment and conveyance facilities to determine existing conditions and remaining service life of the facilities. Field reconnaissance and condition assessment inspections were performed to provide additional data for determining existing conditions.
The two treatment plants (WWTP #1 and WWTP #2) have a combined total design storm flow of approximately 40 MGD. Four alternative sites were identified for a consolidated treatment plant, and associated conveyance alternatives were developed for each alternative. The natural drainage patterns for the existing treatment plant service areas indicate flow from north to south along Bear Branch southward to Lake Woodlands and southward from Lake Woodlands along Panther Branch. Conveyance alternatives included a combination of gravity sewers where depths were 25 feet or less and lift stations and force mains. Conveyance alternatives were developed to maximize gravity conveyance.
Construction costs for treatment consolidation and associated conveyance facilities are estimated to range between $100M and $150M.
Key staff: WWilshire, EBianco, ROrtega
Conveyance of approximately 20 MGD from an existing WW plant to another WW (to be expanded) through a fully developed, high-value residential area, diversion of collection flows from various existing WW lift stations, construction impacts to traffic and daily operations throughout the area were the primary challenges of this project. Proposed gravity sewers and force mains were routed along existing easements and ROW where available. Two lift stations were recommended for upgrades to avoid higher construction costs for building new stations. Five existing lift stations were confirmed for removal from service as a result of the proposed 48” gravity interceptor for conveying flows from SJRA’s WW Plant 2 to WW Plant 1 site. Detailed traffic controls plans will be required to mitigate impacts to traffic during construction. Also, it was recommended that when practical and feasible, construction work be performed outside of the typical workday commute hours of 7:00am to 9:00am and 4:00pm to 6:00pm.