GO Bond Prop A - Flood Protection and Drainage Update
This update for September highlights progress on the Proposition A Flood Protection and Drainage Improvements from the 2019 GO Bond. In May 2019 voters approved general obligation bonds allocating $73 million for 21 drainage projects. The bulk of the projects will provide drainage improvements in and around several League City subdivisions.
Four projects have been completed which include the City Wide 2D Modeling, Bay Ridge Ph 3, Oaks of Clear Creek Overland Flow, and Bradshaw Ditch/Southeast Detention Pond, Dove Meadows Detention Pond. Overall, the status of the program is as follows:
2 Currently under construction
12 Currently under design
1 Scheduled for purchase in 2023
Bay Colony Area Detention Ponds
This project constructs drainage improvements to 18 existing detention ponds to reduce flooding in the Bay Colony area subdivisions. Detention areas are to be widened at the top, leaving the bottom one third of the detention area unchanged. This approach allows for approximately 70 ac-ft of additional detention storage.
Grading improvements of the ponds have been completed. They are now working on the completed ponds by watering and seeding to reestablish vegetation and cleaning up debris. The project is expected to reach substantial completion this summer.
Bay Ridge Phase 2 Pump Station
Phase 2 is the third of four planned projects impacting the Gum Bayou Watershed and the Bay Ridge Subdivision to enter construction. These drainage projects will help with street ponding and reduce the flooding potential during major rainfall events. This project adds capacity to the current detention pond by deepening it and adds a dedicated pump station to pump storm water out of the pond and into Gum Bayou after a major rainfall event. Subdivisions/areas affected include Bay Ridge Area, Hidden Lakes, Whispering Lakes, and Lakes of South Shore.
The contractor commenced pouring the access roadway. The access road is slated to complete within 3 – 4 weeks. The contractor is also installing the discharge lines in preparation for the pumps. Construction is currently scheduled to complete in November 2023 but is highly weather dependent since construction takes place in a pond.
Brief updates of some of the projects in design are below.
Phase 4 of the Bay Ridge Flood Reduction program focuses on Gum Bayou. Proposed culverts at the Columbia Memorial Parkway and League City Parkway were analyzed to determine the appropriate size to reduce ponding and the potential overflows. Hydrology and hydraulics (H&H) studies of Gum Bayou from League City Parkway (SH 96) to Dickinson Bayou were conducted in an effort to provide improvements to allow Bay Ridge Subdivision’s detention to drain. Existing Gum Bayou bridges were a part of the hydraulic analysis. This study helped evaluate the flow of water heading towards Dickinson Bayou in order to provide options for drainage improvements for the Gum Bayou Watershed. The City is currently evaluating the final scope of the project with the consultant.
The Meadows Subdivision Drainage Improvements Project will address chronic flooding by providing clear, unobstructed drainage flow along drainage easements in the subdivision. The design includes adding overflow swales, deepening the existing channel, and upsizing the culvert at Smith Lane. City staff had a meeting with the design consultant in Mid-March to discuss the final design plans prior to submittal. The 100% design was submitted in early April and the City has completed its review. A public meeting was held with The Meadows HOA in mid June to discuss the project prior to bid advertisement. The revised 100% design was submitted at the end of June and was approved and signed by the City at the end of August. City staff is currently coordinating with the HOA for donation of drainage easement to provide a drainage swale.
The Magnolia Creek & Cedar Gully Channel Improvements include modification of Magnolia Creek, Cedar Gully, and related tributaries to be regraded/sized to accommodate for Atlas 14. This is to ensure the drainage of Westover Park, Countryside, Magnolia Creek and Rustic Oaks subdivisions into the system is meeting design standards and does not result in structural flooding within the neighborhoods. Desnagging of the waterways will need to take place with this work. USACE permit comment response letter was submitted October 28, 2022. Additional correspondence was received from the USACE on May 16th with additional comments. The project team held a teleconference with USACE staff in June to discuss the project as a whole. Comments were addressed and submitted back to the USACE. In July 2023 the USACE issued another public notice for the project. Additional comments and correspondence from reviewing agencies was forwarded to the City and consultant in mid August. These comments will be addressed, and a response sent back to the USACE by mid September.
Design plans and specifications are complete and ready for bid advertisement for the Countryside Subdivision Drainage Improvement. The City held a public meeting with homeowners in September 2022 and based on their recommendations, the City will reevaluate flooding observed and reported after Hurricane Harvey. The City will also clear out debris in the existing outfalls to Magnolia Creek. A meeting with Countryside South Community Association was held on March 8, 2023 to discuss the project scope and answer resident concerns. The project will be moving forward to bid in the next couple of months. Final scope will be dependent on the HOA and resident concurrence with the improvements as proposed.
Bay Ridge Flood Reduction – Phase 1 Levee Improvements will elevate the front 400’ of Bay Ridge Drive, which was determined to be the main risk of flooding from external flood sources. The consultant is currently revising construction plans to add a retaining wall to the plans in order to reduce the necessary easement acquisition to construct the project. One hundred percent (100%) designs have been accepted by the City. Plans were also submitted to TxDOT for review. The consultant has met with TxDOT to review the drainage design and determine if any additional permits are require. A temporary construction easement is being negotiated with adjacent property owner. A final date for bid has not been determined.
The Benson Bayou Detention Project – Phase 1 will provide critical detention improvements within the watershed coupled with grade adjustments to the existing bayou in efforts to reduce water surface elevations to benefit the area while ensuring no adverse impact to downstream neighbors. In June 2022 an environmental investigation of a proposed pond site revealed a large number of forested wetlands within the proposed project area. The City directed the consultant to revise the project scope of work and design to remain within the approved budget for the project. The consultant delivered the revised schematic design on July 22, 2022, which included several alternative options to construct the detention basin within a smaller project footprint. City staff has requested that the consultant also explore the possibility of expanding an existing pond in the in the area and constructing a pump station. The report was received and was submitted to engineering for review. The City has reviewed and is determining whether the revised scope of the project is more cost effective, feasible, and within the approved budget.
The FM518 & Wesley Dr Drainage Improvements project focuses improvements on capturing and conveying the stormwater runoff that exceeds the current storm sewer system capacity at the intersection of FM 518 and Wesley Drive. The improvements will include upsizing and installing a new storm sewer system to convey stormwater to Corum Ditch. The project will incorporate current drainage and stormwater design standards. The Texas General Land Office (GLO) approved the AUGF (Authority to use Grant Funds) on February 21st. The LOSA (Local on System Agreement) has been submitted to TxDOT and is under review. 100% plans were approved by the City on Augusty 03, 2023. Utility relocation is currently ongoing along the northern right-of-way of FM 518. Construction is anticipated to start in early 2024.
The Oaks of Clear Creek North Detention Pond will reduce structural and street flooding in the Oaks of Clear Creek Subdivision in conjunction with the improvements from the Oaks of Clear Creek Detention and Deer Ridge Drive Overland Flow Projects. Purchase of land required for the drainage easement is in progress. The consultant is working on the environmental assessment (EA) and cultural resources study. GLO has reviewed and accepted the Environmental Assessment (EA) for Oaks of Clear Creek. The Authorization to Use Grant Funds (AUGF) was received in mid-July.
The Hughes Lane and W. Deats Rd Culvert Modification Project will increase capacity and efficiency of drainage flows through Borden’s Gully to I-45. Revised 30% design plans were received in October 2022 and design coordination between the City of League City and City of Dickinson design consultants progressed through April 2023. The City’s consultant was given authorization to proceed with 60% design in May 2023.