instream flow study for the proposed lower bois d’arc...

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



• Fluvial Geomorphology – Sediment transport – Mesohabitats




• Biology – Fish and macroinvertebrates




• 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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Flo

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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*



Baseflowa 3 Normal – Wet July – March

Baseflowb 10 Normal – Wet April – June



Flow Component

Release Amount*





High Flow Pulse 50 Normal – Wet 1 in spring 1 in summer



Flow Component

Release Amount*





High Flow Pulse 50 Normal – Wet 1 in spring 1 in summer

Overbank Flows NA NA NA




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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

instream flow study for the proposed lower bois d’arc...

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