Title
Consider and take action on a resolution authorizing an amendment to the professional services agreement with LJA Engineering, Inc. to increase compensation in an amount not to exceed $119,000 for additional preliminary design services related to the Bay Ridge Flood Reduction Phase 4 Project (DR1904) for an aggregate amount not to exceed $788,348 (Executive Director of Capital Projects)
Background:
Approval of this resolution will authorize Amendment 1 to professional services agreement LJA Engineering, Inc. for additional preliminary design services related to the Bay Ridge Flood Reduction Phase 4 Project (DR1904) in an amount not to exceed $119,000.
In the aftermath of the Hurricane Harvey flooding, City Staff began working with LJA Engineering to conduct a high-level Hydrologic & Hydraulic (H&H) Study of areas within the Gum Bayou Watershed and the Bay Ridge Subdivision. A contract was executed with LJA Engineering in October 2017. On March 22, 2018, City Staff and LJA held a public meeting to go over the preliminary findings of the study and to discuss potential improvements to help reduce flooding within this area.
In August 2018, the final report was presented to City Council during a Council Work Session. One of the areas of concern discussed during the public meeting and again when presenting to Council was the deficiencies related to detention and conveyance in and along Gum Bayou, which can lead to water not draining properly into the bayou. This type of issue was experienced by the residents of Bay Ridge and the Lakes of South Shore. Several retail and commercial properties in the area along Hwy 96 also experienced problems with proper drainage due to the limitations of Gum Bayou. To a lesser extent, similar issues were observed in the Hidden Lakes Development and the Education Village areas. While Hurricane Harvey was mostly a rain event (4 to 6 feet of surge experienced), weather events that cause high surge levels (such as Hurricane Ike), when coupled with moderate to heavy rainfall, can further exacerbate the issues along Gum Bayou.
In June 2019, an agreement was executed with LJA Engineering for Gum Bayou specific H&H study and preliminary engineering. The results of this study were presented in the September 2021 report showing that Gum Bayou can be widened within its existing easement but approximately 275 acre-feet of detention is required around or to south of FM 646. An opportunity arose in 2023 for City to acquire some detention capacity in a planned development south of FM 646. The City and Lakeside Bayou LLC executed an agreement in 2024, and City purchased 200-acre feet detention capacity in development’s proposed detention facility.
This Amendment 1 responds to City staff’s request for revisions to the previously approved hydrology and hydraulic analysis to update drainage conditions based on the eventual implementation of the 200-acre feet detention in Lakeside Bayou, LLC development and determining if additional detention is required and study options and providing costs for Gum Bayou improvements. LJA Engineering has been tasked with revising the existing drainage impact analysis to incorporate new development parameters, evaluate the cumulative impact of proposed improvements, and utilize excess detention volume available in the Lakeside Bayou Development ponds.
The scope of work includes updates to both hydrologic (HEC-HMS) and hydraulic (HEC-RAS) models, preparation of a revised drainage report, and the creation of preliminary design exhibits.
The revised analysis is expected to address existing and proposed drainage scenarios, including volume verification, runoff impact mitigation, and necessary design modifications to ensure compliance with City standards. Additionally, LJA will participate in public and council meetings to present findings and receive stakeholder input.
This Amendment 1 increases the original contract value by $119,000, adjusting the total compensation from $669,348 to $788,348. The revised work is anticipated to be completed over a 200-day schedule, excluding City review periods. The final design scope will be defined after completion of this study for development of construction plans.
For this amendment, the following tasks and associated fees will be as follows:
Revised Preliminary Design (Lump Sum) $ 20,000
Meetings (Time & Material) $ 5,000
Revised Hydraulic & Hydrology Analysis (Lump Sum) $ 91,500
Reimbursable Expenses (Time & Material) $ 2,500
TOTAL $119,000
Attachments:
1. Proposed Resolution
2. Exhibit A - Amendment #1 with Proposal
3. LJA Executed 2019 Agreement
4. CIP Project Sheet
5. CIP Aerial Map (Modif.)
6. Vendor Report Card
FUNDING
{X} Funding in the amount of $119,000 is available from fund 5270, PROP A 2021 Issuance, with expenses charged to project expense string DR1904-PLAN DESIGN-DESIGN- 21PROPA.
STRATEGIC PLANNING
{X} Addresses Strategic Planning Critical Success Factor #1: Develop and Maintain our Infrastructure.