GO Bond Prop A - Flood Protection and Drainage Updat
This update for June 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 Phase 3, Oaks of Clear Creek Overland Flow, and Bradshaw Ditch/Southeast Detention Pond. Overall, the status of the program is as follows:
4 Complete
4 Currently under construction
12 Currently under design
1 Scheduled for purchase in 2023
Construction
Bay Colony Area Detention Ponds
https://www.leaguecitytx.gov/3444/Bay-Colony-Area-Detention-Modifications
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 to over 90% of the ponds has been completed, including at Bay Colony Town Center, Bay Colony Parkside Community, Bay Colony Meadows East Detention Pond, Bay Colony Pointe Subdivision and Lakes of Bay Colony. The contractor is currently working on the ponds at Meadows of Bay Colony and completing restoration of all ponds associated with the project. The project is expected to reach substantial completion this summer.
Bay Ridge Phase 2 Pump Station
https://www.leaguecitytx.gov/3445/Bay-Ridge-Flood-Reduction-Phases-I-IV
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.
Pond excavation will be ongoing for the next several months. Construction of the Pump station building pad started in January. In late February an older existing sanitary sewer line was found to conflict with the pump building pad and discharge piping. The conflict was resolved in May via rerouting the sewer line around the building improvements. Construction of the foundation and walls for the pump station is complete. The contractor began forming and pouring the pilot channels. Construction is currently scheduled to complete in November 2023 but is highly weather dependent since construction takes place in a pond.
Dove Meadows Detention Pond
https://www.leaguecitytx.gov/3451/Dove-Meadows-Detention-Pond
This project will construct an approximately 15-acre detention pond and shelf cut along Borden’s Gully adjacent the Dove Meadows Subdivision to reduce structural flooding in the Dove Meadows Subdivision. The subdivision is impacted by existing drainage culverts at Hughes Lane and West Deats Road that are not properly sized based on current design standards. The area is also impacted by the condition of Dickinson Bayou downstream of these culverts within the City of Dickinson. The Dove Meadows Subdivision is the first in this area to see the impacts of the back-up due to undersized crossings and the existing condition of Dickinson Bayou. The added detention will help reduce the potential for structural flooding in Dove Meadows.
The contractor is continuing the excavation of approximately 130,000 cubic yards of dirt from the site to construct the detention pond to create added capacity. The contractor completed the excavation of the shelf-cut area along Borden’s Gully in January and constructed the concrete weir in February. Forming and pouring of the pilot channels will be ongoing. Rain has slightly delayed this project, along with the relocation of the water line which was unforeseen. Contractor is performing restoration work and revegetation of the site to prepare for substantial completion but the pond is functioning as designed! Expected completion of this project is Summer 2023.
Clear Creek Tributaries Clearing & Desnagging Project
https://www.leaguecitytx.gov/3951/Clear-Creek-Tributaries-Select-Clearing-
This study determined that selective clearing and desnagging of select Clear Creek tributaries would increase capacity. The project area includes the following channels within League City, Texas: Cedar Gully from FM 518 (Main Street) to Magnolia Creek, Landing Ditch from FM 518 to Clear Creek, Newport Ditch from FM 518 to Landing Ditch, Magnolia Creek from FM 518 to Clear Creek.
The contractor mobilized at College of Mainland the week February 20th and began clearing. Tree clearing activities will continue through June 2023. Installation of slope paving has started as well.
Design
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 is currently scheduled with The Meadows HOA in mid June to discuss the project prior to bid advertisement.
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. Correspondence was received from the USACE on May 16th with additional comments. The project team is trying to request a meeting with USACE staff to discuss the concerns. 100% submittal will be held until comments received by USACE.
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. Revised drawings will be submitted to the City for review by the end of the month.
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 at the end of April. The City will review and determine 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. Centerpoint gas lines in the TxDOT ROW that are in conflict need to be relocated. The LOSA (Local on System Agreement) has been submitted to TxDOT and is under review. 100% plans were submitted for interdepartmental review on April 15th and City Staff provided comments back on May 23rd. Dependent on TXDOT approving the LOSA, construction is anticipated to start in fall 2023.
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.
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.