Dallas Water Utilities Presentation to Friends of Bachman Lake
Embankment
Water Facilities Program Management & Stormwater Operations Dallas Water Utilities
August 10, 2020 Agenda: • Introductions • Project Goals and Timelines for Lake Dredging and Dam and Spillway Maintenance Improvement Projects • Bachman Lake Water Quality Sampling and Analysis Update • Bachman Lake Stormwater Inlet Cleaning and Maintenance Status Report • Questions?
2
Bachman Lake Dam and Spillway and Lake Dredging Maintenance
Improvements Project.
Embankment
Marc Cottingame, P.E. DWU Program Manager Mark S. Mihm, P.E. DWU Project Manager
Water Facilities Program Management Dallas Water Utilities Dallas Water Utilities Project Team
Team Member /Contact Information Role
Mark S. Mihm, P.E. Project Manager 214-670-4271 Water Facilities Capital Improvements [email protected]
Marc Cottingame, P.E. Senior Program Manager 214-671-9170 Water Facilities Capital Improvements [email protected]
Matt Penk, P.E. 214-671-9560 Assistant Director Capital Improvements [email protected]
5 Background
6 Bachman Lake Dam
• Dam was Built in 1901 • Bachman Lake • Originally used for Water Supply • Converted to Recreational Use in 1960’s Image • 35’ Tall Earthen Embankment • 180’ Long Concrete Overflow Spillway
7 Bachman Lake Dam - Key Features
8 Early Project Drivers • 2016 Love Field / Bachman Lake Feasibility Study • Bachman Lake Task Force Recommendation to “Maintain the Lake” • Provide Design, Bidding, and Construction for Lake Dredging and Bachman Lake Dam and Spillway Reconstruction
9 Project Goals & Timelines
1 0 Project Objectives
• Update hydrology and hydraulics of the Bachman Dam and Spillway
• Meet required regulatory flood capacity
• Remove sediment to return lake to recreational levels
• Address Bachman Dam structural and stability recommendations
1 1 Why these Projects are Important • Preserve Dam Integrity • Restore Water Depth for Recreational Use • Maintenance of Embankment and Spillway • Trees / Underbrush • Erosion • Seepage
1 2 Project Timelines Timeline Project Activity
June 2020 Dredging Design and Field Work Tasks for Freshwater Mussel Survey, Bathymetric Survey, Cultural Resources, Topographic Survey, and Geotechnical Investigation.
Late Summer 2020 Public & Bachman Lake Stakeholders Meeting to present project overview and gather input. August 2020 meeting with Friends of Bachman Lake (FoBL).
Winter 2020/2021 Complete Dredging Design and Advertisement for Dredging Bids. Complete Dam Rehabilitation Final Design Report. Public & Bachman Lake Stakeholders Meeting to present Project Update
Spring 2021 Open Bids for Dredging Services, Council Consideration of Dredging Construction Contract Begin Final Design Phase 2A of Dam Rehabilitation Spring/Summer 2021 Begin Bachman Lake Dredging Work
Fall 2021 Complete Dam Rehabilitation Design and Advertisement for Bids
Winter 2021 Completion of Bachman Lake Dredging and Demobilization. Council Consideration of Dam Rehabilitation Construction Contract
Spring 2022 Begin Dam Rehabilitation Construction
Summer 2023 Completion of Dam Rehabilitation Construction and Demobilization Project Progress
1 4 Completed Field Activities for Permitting and Design
• Topographic Survey of the Lake for Dam Design • Fresh Water Mussel Survey for USACE • Bathymetric Survey to Estimate Dredging Volume • Geotechnical Investigation for Dam Design • Waters of the US Survey for Wetlands Delineation • Cultural Resources Survey for Permitting
1 5 Fresh Water Mussel Survey for USACE and TPWD Typical Hydraulic Dredging Barge Used in Lakes Project Milestone Summary
• Fieldwork for TCEQ, USACE and US Fish & Wildlife is Complete, and Reports are Filed with Agencies
• Dredging Design Completion – Winter 2020/2021
• Begin Dredging Work – Spring/Summer 2021
• Final Design Report for Dam Rehab – Winter 2020/2021
• Dam and Spillway Design Completion – Fall 2021
• Dam Reconstruction Completion - Summer 2023 Stormwater Operations Water Quality Program Neighborhood Drainage Services
Embankment Sergio Munoz Program Manager (I) Neighborhood Drainage Services
Nusrat Munir Environmental Manager II Neighborhood Drainage Services Dallas Water Utilities Stormwater Operations Project Team
Team Member /Contact Information Role
Sergio Munoz . Senior Program Manager (I) 214-671-2136 Neighborhood Drainage Services [email protected]
Nusrat Munir Environmental Manager II 214-948-4303 Neighborhood Drainage Services [email protected]
Sarah Standifer Assistant Director 214-671-9581 Stormwater Operations [email protected] Stormwater Operations Overview Stormwater Operations Stormwater Operations is obligated to regulatory compliance through the (MS4) permit and USACE for the Dallas Levee System and other improvements related to the Waters of the US. Trinity River Watershed One of 23 Major Texas Watersheds Extends from Oklahoma to Gulf of Mexico Approximately 6,050 sq. miles Above Dallas Drainage System Infrastructure
•1,800 miles of storm sewers •30 miles of levee •13 pump stations at 8 locations •6 pressure sewers •8 street pump stations •~661 miles channel* •~39,000 acres floodplain * Includes both public and private channels Water Quality Program
The City of Dallas is permitted for the Municipal Separate Storm Sewer System through the Texas Commission on Environmental Quality.
The program includes several components including the maintenance of the Storm Sewer System and the Surface Runoff Water Quality Testing Programs. Water Quality Program
The Surface Runoff Water Quality includes 120 sites across the City
• 28 - Local Wet Weather Sites (includes TCEQ outfalls)
• 12 - Regional Wet Weather Sites; in collaboration with North Central Texas Council of Governments (NCCOG)
• 72 - Bioassay Sites • 26 - Macroinvertebrate (Bug) Sites along with water quality samples • 46 - Water Quality Sites Water Quality Program (Dry Weather Inspections)
• There are roughly 7,500 outfalls that are inspected during a 5-year permit term
• Flows are sampled and analyzed to determine source such as ground water, sprinkler discharge or an illicit discharge
• Illicit discharges are tracked to the source and the responsible party is notified to remedy the discharge
• OEQS is notified if illicit discharge is found to be from a construction/industrial site Water Quality Program (Stormwater Service Requests) Top three emergency response calls across this City:
• Water Pollution
• Fish Kills
• Internal Sampling
The public is advised to call 3-1-1 to report any water quality concerns. Water Quality Program (Special Projects)
• Water samples of tributaries are conducted monthly or quarterly:
• Quarterly - Trinity River Authority (Clean Rivers Program)
• Monthly – Pavaho, Bachman Lake and Kidd Springs Pond
• Litter Booms – inspected monthly (Bachman Lake, White Rock Lake and Lake Cliff). Floatation booms which collects floatable trash and prevents items from entering a connecting waterbody. Reports are sent to appropriate personnel within Parks & Recreation detailing trash accumulation and maintenance if needed. Water Quality Program (Special Projects cont'd)
• TMDL (Total Maximum Daily Load) - new program implemented to help reduce bacteria levels in creeks throughout City of Dallas watersheds. Samples are collected intermittently (during dry periods & post rain events) to trace and identify point source pollutant infiltration. Water Quality Sampling Locations (Bachman Lake)
• Three sampling sites: (BACL1, BACL2 & BACL3)
• The upstream location (1) was on the downstream side of the Lemmon Ave. bridge, the midstream location (2) was at the middle point of the lake and the downstream location (3) was located just upstream of the Denton Dr. bridge. Bachman Lake Sampling Project
The water quality samples were collected according to the sampling plan designed to obtain the water quality information for Bachman Lake located at 3500 W Northwest Hwy., Dallas, TX.
Standard EPA methods and procedures were employed to collect data to determine the water quality of the lake while comparing the water quality of the upstream and downstream locations. Acronyms Bachman Lake Sampling List of Parameters
The Sampling Plan includes the following parameters to be analyzed:
DO, pH, Conductivity, Ammonia, Nitrates-Nitrites, Total Phosphorus, Hardness, Chlorine, Metals (Cu, Fe), TSS, Turbidity and E. coli.
No samples for TPH/BTEX and PAH were collected as no hydrocarbon sheen was observed on the water surface. Monthly Samples Site Geomeans
Site ID GeoMean BACL-1 70 BACL-2 36 BACL-3 84 Monthly Ammonia Results Monthly Nitrogen Results Monthly Phosphorus Results Statistical Analysis: Bachman Lake Water Sampling
• The statistical analyses of the data determined the water quality of Bachman Lake was compliant with the Texas Surface Water Quality Standards set by the TCEQ. References
• TCEQ - Texas Surface Water Quality Standards, Chapter 307, Rule Project No. 2012-001-307-OW
• EPA Standard Method 21st Edition
• EPA-SW-846 Online, Series 3000
• EPA-SW-846 Online, Chapter Three (Inorganic Analytes) Bachman Lake Stormwater Inlet Cleaning
4 3 Neighborhood Drainage Services
The Neighborhood Drainage group is responsible for the removal of blockages on City-owned inlets, creeks/channels (except creeks and channels located in Parks), storm sewers, and responds to inclement weather emergencies such as snow/ice, windstorms and street flooding. Bachman Lake Inlets Area Map Inlets Inspected and Cleaned April 2, 2020 Maps 1 and 2 Inlets Inspected and Cleaned April 2, 2020 Maps 3 and 4 Inlets Inspected and Cleaned April 2, 2020 Maps 5 and 6 Bachman Lake Cleaned Inlets Stormwater Inlet Cleaning Schedule
All 25 inlets around Bachman Lake were cleaned on April 2, 2020. Additionally, all inlets and outlets leading to the lake were cleaned August 5, 2020.
50 Questions?
51 Sampling Results: January 1, 2020 – June 2, 2020