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BY JON ALBRIGHT
Instream Flow Study for the Proposed Lower Bois d’Arc Creek Reservoir, Texas
RiverWare Users Group February 1, 2012
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Topics • Lower Bois d’Arc Creek Reservoir Instream Flow
Study • Challenges modeling environmental flows
associated with the Texas Instream Flow Program
Bonham
Proposed Reservoir
Honey Grove Dodd City Windom
Ravenna
Ladonia
Leonard
Ector
Owner North Texas Municipal Water District
Surface Area 16,526 acres Drainage Area 327 sq. miles Storage 367,609 ac-ft Supply 113 MGD Avg/Max Depth 22 ft/70 ft Elevation 534 ft msl
Lower Bois d’Arc Cr Reservoir
Instream Flow Study
• Based on Texas Instream Flow Program • Multidiscipline
– Field work – Modeling
• Objectives – Characterize existing conditions – Evaluate impacts of the proposed reservoir on
Bois d’Arc Creek – Recommend a flow regime to maintain a Sound
Ecological Environment
Sound Ecological Environment
• Stream power to move sediment, but not create excessive erosion
• Support mesohabitat diversity • Provide hydraulic connectivity • Maintain water quality • Support fish reproduction • Maintain or improve fish and
macroinvertebrate communities
Study Components • Hydrology and Hydraulics
– Flows over time (seasonally and long-term) – Hydraulic connectivity to support biology
Study Components • Hydrology and Hydraulics
– Flows over time (seasonally and long-term) – Hydraulic connectivity to support biology
• Fluvial Geomorphology – Sediment transport – Mesohabitats
Study Components • Hydrology and Hydraulics
– Flows over time (seasonally and long-term) – Hydraulic connectivity to support biology
• Fluvial Geomorphology – Sediment transport – Mesohabitats
• Biology – Fish and macroinvertebrates
Study Components • Hydrology and Hydraulics
– Flows over time (seasonally and long-term) – Hydraulic connectivity to support biology
• Fluvial Geomorphology – Sediment transport – Mesohabitats
• Biology – Fish and macroinvertebrates
• Water Quality – Dissolved oxygen and temperature
Hydrology
• Data Sources and Models: – USGS gages (Bois d’Arc Creek, North Sulphur,
others) – Field data – Cross-section surveys and LiDar survey – HEC-RAS (hydraulics and habitat modeling)
• Full model – high flows • Reach models – low flows
– RiverWare (long-term watershed modeling)
Hydrology • Limited historical data
– Drainage area ratios and rainfall/runoff trends – Monthy Red River WAM flows to daily – Long-term behavior from RiverWare models
• Channelization – Flashy (rapid rise and fall) – Frequent high flows
cause erosion – Extended periods of
little to no flow
Flow Duration Curves
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Percent of Time Equaled or Exceeded
Full Period
April-June
July-October
November-March
Existing Conditions • Three Reservoirs
– Lake Bonham – Coffee Mill Lake – Crockett Lake
• One water users • Three reach objects • Four control points • Lake Bonham to Red
River
Future Conditions • Four Reservoirs
– Lake Bonham – Coffee Mill Lake – Crockett Lake – Lower Bois d’Arc Cr
Reservoir
• Two water users • Three reach objects • Two control points
Reservoir Storage
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Stor
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(ac-
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Date
Lower Bois d'Arc Storage 40% of Conservation Storage Conservation Storage
Flow Component
Release Amount*
(cfs) Condition Duration
Subsistence 1 Drought Based on Conditions
* Subsistence flow triggered when reservoir is less than 40 percent full. Pulse flow would be released seasonally if such flows do not occur naturally.
Proposed Flow Regime
Flow Component
Release Amount*
(cfs) Condition Duration
Subsistence 1 Drought Based on Conditions
Baseflowa 3 Normal – Wet July – March
Baseflowb 10 Normal – Wet April – June
* Subsistence flow triggered when reservoir is less than 40 percent full. Pulse flow would be released seasonally if such flows do not occur naturally.
Proposed Flow Regime
Flow Component
Release Amount*
(cfs) Condition Duration
Subsistence 1 Drought Based on Conditions
Baseflowa 3 Normal – Wet July – March
Baseflowb 10 Normal – Wet April – June
High Flow Pulse 50 Normal – Wet 1 in spring 1 in summer
* Subsistence flow triggered when reservoir is less than 40 percent full. Pulse flow would be released seasonally if such flows do not occur naturally.
Proposed Flow Regime
Flow Component
Release Amount*
(cfs) Condition Duration
Subsistence 1 Drought Based on Conditions
Baseflowa 3 Normal – Wet July – March
Baseflowb 10 Normal – Wet April – June
High Flow Pulse 50 Normal – Wet 1 in spring 1 in summer
Overbank Flows NA NA NA
* Subsistence flow triggered when reservoir is less than 40 percent full. Pulse flow would be released seasonally if such flows do not occur naturally.
Proposed Flow Regime
Proposed Flow Regime
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(cfs
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Percent of Time Equaled or Exceeded
Post Dam Full Period Pre-Dam Full Period
Challenges Modeling TIFP
• Base and pulse flows • Monthly water availability models • Pulses
– Identification – Prediction
• Credit for pulses – Without a release – With a partial release
Status
The proposed instream flow regime for the Lower Bois
d’Arc Creek Reservoir is under review by the Texas
Commission on Environmental Quality as part of its
processing of the North Texas Municipal Water District’s
application for a water right permit for the project. No
approval or acceptance of the proposed flow regime has
been issued by any state or federal regulatory agency as
of this date.
Acknowledgements • Project Sponsor: North Texas Municipal Water District
• Field Data Collection: – Texas Commission on Environmental Quality – Texas Parks and Wildlife Department – Texas Water Development Board – Freese and Nichols, Inc.
• Technical analyses: – Simone Kiel – Steve Watters – Stephanie Coffman – Randall Howard
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