Incorporating Basin Technical and Scientific Advisory Committee - - PowerPoint PPT Presentation

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Incorporating Basin Technical and Scientific Advisory Committee - - PowerPoint PPT Presentation

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Incorporating Basin Technical and Scientific Advisory Committee Recommendations into Local Projects Chad Engels, PE Bois de Sioux Watershed District Engineer 2019 Red River Basin Drainage Conference Marriott Hotel and Convention Center,

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Incorporating Basin Technical and Scientific Advisory Committee Recommendations into Local Projects

Chad Engels, PE Bois de Sioux Watershed District Engineer 2019 Red River Basin Drainage Conference Marriott Hotel and Convention Center, Moorhead, MN March 19th, 2019

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Overview

1. Bois de Sioux Watershed District (BdSWD) Background 2. Basin Technical & Scientific Advisory Committee (BTSAC) Papers 3. BTSAC Applications for Permitting 4. BTSAC Applications for 103E Public Drainage Systems 5. BTSAC Applications for Watershed Projects 6. Summary

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BOIS DE SIOUX WATERSHED DISTRICT

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Background

Bois de Sioux Watershed District

  • Formed in 1988
  • Headwaters of the Red River
  • 1,412 square mile watershed
  • 6 Counties (9 Water Managers)
  • Administrator, Office Manager, & Technician
  • Major Tributaries: Mustinka & Rabbit Rivers
  • One Watershed One Plan (2 WRAPS Complete)

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Background

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Background

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Mustinka Rabbit White Rock Dam

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Background

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1997 FEMA DAMAGE SITES

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2019 Spring Flood Outlook

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Snow Water Equivalent – March 17, 2019

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BASIN TECHNICAL & SCIENTIFIC ADVISORY COMMITTEE (BTSAC) PAPERS

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Volume & Rate Considerations

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  • Volume = the amount of water (ac-ft or ft3)
  • Rate (Discharge) = the movement of water (ft3/s)
  • Red River Basin floods tend to be volume driven
  • Extent of flooding in the flat glacial lake plain
  • How does subsurface drainage affect volume?
  • Potential loss of soil storage (dry soil condition vs. wet soil condition)
  • How does surface drainage affect volume?
  • Possible addition of previously non-contributing areas
  • Possible reduction of temporary floodplain storage
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  • BTSAC Briefing Paper No. 2
  • Water Management Options for Sub-surface Drainage (2012)
  • BTSAC Briefing Paper No. 3
  • Water Management Options for Surface Drainage (2014)

BTSAC Briefing Papers

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Briefing Paper No. 3 (Surface)

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  • Sponsored by the

ND RRJWRD and MN RRWMB

  • What are the

impacts of ag drainage on peak watershed flows?

  • How should ag

drainage systems be designed and managed? Briefing Paper #3 BTSAC Members (20)

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  • Key BTSAC Surface Water Management Statements
  • Landowners have a right to adequate, but not more than adequate, drainage
  • Adequate drainage is defined as the capacity to remove a 10-yr 24-hr summer

rainfall event without significant crop damage (removal in 24 hrs)

  • Typical 10-yr rainfall at center of RRB is 3.6 inches in 24 hrs (1.3 inches runoff)
  • Equal distribution of positive and negative drainage impacts throughout the

system is the design goal

  • “Uniform Surface Drainage Design Guidance” for small watersheds
  • “Self Mitigating” Design

Briefing Paper No. 3

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  • Equal distribution of positive and negative impacts

Briefing Paper No. 3

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Oversized Culverts “Adverse Downstream Impacts” Properly Sized Culverts “Self Mitigating Design” Temporary Floodplain Storage for an Event Exceeding the System Design

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  • “Uniform Surface Drainage Guidance”
  • BTSAC Design Flow = Q

BTSAC Briefing Paper #3

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  • “Uniform Surface Drainage Guidance” – Design Steps
  • Determine Q for each design location (typically each road crossing)
  • Design the upstream channel to convey Q with ½ to 1 foot of freeboard
  • Design the culvert for ½ to 1 foot of headloss
  • The design water surface profile upstream of crossings should be at field El.
  • Spoil banks must be lowered to the design El. immediately upstream of crossings
  • Flap gates (trap gates) are allowed if spoil banks are lowered
  • Crop damage is expected for events larger than the 10-yr
  • This design guidance is for small watersheds of relatively flat to moderate slope
  • Self mitigating design

BTSAC Briefing Paper #3

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  • “Uniform Surface Drainage Guidance”

BTSAC Briefing Paper #3

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Temporary Floodplain Storage

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  • Water Management Options for Sub-surface Drainage (2012)
  • Recommends outlet controls for subsurface drainage – Preferred
  • Recommends “on or off-site” storage alternative (mitigate lost soil storage)
  • Recommends lower “Drainage Coefficients” (slow release of water from the soil)
  • Recommends culvert sizing strategy (temporary short term on-channel storage)

BTSAC Briefing Paper #2 (Sub-surface)

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1998 Mediation Agreement

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  • Key Mediation Agreement Statements that “fit” with BTSAC
  • The broad goals for flood damage reduction in the Basin are:

− To reduce damage to farmland by providing protection against the 10-yr storm event for intensively farmed ag land

  • Culvert sizing is a flood damage reduction strategy

− Graduated sizing of culverts in ditch systems provides control − Equity is an important consideration − The smaller the drainage area the more effective culvert sizing becomes

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PERMITTING

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Permitting

BdSWD Permitting Authority

  • Private Subsurface Drainage (Tile)
  • Private Surface Drainage
  • Culverts & Bridges
  • Ring Dikes & Levees
  • Alterations to Rivers, Streams,

Wetlands, Shorelines, and Roads

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Permitting

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Miles of Permitted Drain Tile Since 2000

Through 2010 Through 2018 18,500 miles in past 19 years Significant increase in miles of tile installed over the past 8 years

  • Approx. 25% of the watershed area is now tiled
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Permitting

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Past 4 Years (2015-2018)

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  • BTSAC Briefing Paper #2 – Water Management Options for Sub-surface Drainage
  • Recommends outlet controls for subsurface drainage
  • Recommends lower “Drainage Coefficients” (slow release of water from the soil)
  • Recommends culvert sizing strategy (BTSAC Paper #3)
  • BTSAC Briefing Paper #3 – Water Management Options for Surface Drainage
  • Recommends utilizing culvert and channel design guidance
  • Recommends maintaining existing non-contributing areas

BdSWD Permit Policies

BdSWD has adopted Basin Technical and Scientific Advisory Committee (BTSAC) Briefing Papers #2 & #3

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  • Gravity Outlets - ¼” DC
  • Controlled Outlets – No DC Limitation
  • Lift Stations
  • Control Structures
  • All pumps must be turned off and

gates closed during all times the District determines flood conditions exist downstream

  • First downstream culvert must

conform to BTSAC 10-yr design

BdSWD Permit Policies (BTSAC)

Sub-surface Drainage (Drain Tile)

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  • Tile Pump Status Webpage
  • Highlights areas in red where pump

restrictions apply within the District

  • EZ Texting Signup
  • Website where permit applicants

can sign up to receive text message alerts regarding pump restrictions

BdSWD Permit Policies (BTSAC)

BdSWD Website

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BdSWD Permit Policies (BTSAC)

Culvert Replacement Permits

  • Culvert Design Requirement (BTSAC)
  • 10-yr BTSAC Design Flow
  • Approx. 1” DC (K = 27)
  • 0.5’ – 1.0’ of Head Loss
  • No permit required for Existing

Culverts if:

  • Proposed culvert has the same

capacity as the existing culvert and set at the same grade

  • Proposed culvert diameter is 18”
  • r smaller
  • All other culvert replacements

require a permit from the District

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103E PUBLIC DRAINAGE SYSTEMS

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103E Public Drainage

103E Public Drainage in the BdSWD

  • 586 miles of 103E Ditches
  • 412 miles are under the

authority of the BdSWD

  • Grant, Stevens, OtterTail and

Big Stone Counties have retained authority

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103E Public Drainage

BTSAC Recommends…

  • “The design guidance should be considered when permitting or

improving both public and private surface drainage systems in agricultural areas of the Red River Basin”

  • “Every available opportunity should be utilized to retrofit

existing Red River Basin drainage systems using this design guidance”

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103E Public Drainage

BTSAC States…

  • “If the design guidance is applied, and culverts

are appropriately sized according to the design guidance throughout the watershed of the drainage system, no further drainage system flood mitigation is needed because the agricultural surface drainage system can be considered self-mitigating”

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103E Public Drainage

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BTSAC Design Elements

FLOW

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103E Public Drainage

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BTSAC Recommendation: Low Spoil Bank Upstream of Road Crossings

10-yr design breakout

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103E Public Drainage

Channel Design - Typical Cross Section

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103E Public Drainage

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Channel Design:

  • Flatten Field Side-Slope
  • Construct Field Berm
  • 20:1 Backslope
  • Grass Buffer
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103E Public Drainage

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R/W includes:

  • Permanent Easements
  • Permanent Spoil

Easements (also used for construction)

  • Const. and Future

Spoil Easement Permanent Easement 103E Buffer

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103E Public Drainage

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  • BTSAC 103E Ditch Retrofits
  • Traverse Co. Ditch No. 37 (2017)
  • Wilkin Co. Ditch No. 8 (2018)
  • Wilkin Co. Ditch Nos. 9 & 10 (2019)
  • Judicial Ditch No. 11 (2020)
  • Judicial Ditch No. 6 (2021)
  • Wilkin Co. Ditch No. 1 (2022)
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103E Public Drainage

BTSAC Cost Share Policy Incentive

  • Road crossing cost share for 103E ditch systems
  • Paid from BdSWD general fund dollars
  • Reimburse 103E ditch for road crossing construction costs
  • Addresses road authority funding challenges
  • Cost Share Policy Rules
  • 103E ditch must be under the authority of the BdSWD
  • Limited to road crossing culverts
  • Culvert sizing must follow BTSAC recommendations
  • Must be in association with an overall “Clean Water Retrofit” of the ditch
  • Pays 100% of construction costs

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103E Public Drainage

BTSAC 103E Ditch Retrofits

  • Successful Project

Outcomes!

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WATERSHED PROJECTS

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Watershed Projects

BTSAC Briefing Paper #2 (Sub-Surface Drainage) Storage Recommendation

  • Impoundments mitigate the risk of

increased floods due to potential lost soil storage volume from uncontrolled tile drainage

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Watershed Projects

  • North Ottawa Impoundment
  • Rabbit River Watershed
  • Controls 74 square miles
  • 16,200 Ac-Ft Gated (4.1”)
  • 18,200 Ac-Ft E.S. (4.6”)

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Watershed Projects

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  • BTSAC BP #2 Drainage Objective:
  • Mitigates potential tile drainage

impacts from lost soil storage

  • Other Drainage Benefits:
  • Provides an “adequate outlet”

for surface drainage

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Watershed Projects

  • Redpath Impoundment
  • Mustinka River Watershed
  • Controls 199 Square Miles
  • 18,800 Ac-Ft Gated (1.8”)
  • 22,700 Ac-Ft E.S. (2.1”)

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SUMMARY

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Summary

  • BTSAC Recommendations are not yet widely adopted
  • Recommendations require voluntary adoption by permitting authorities
  • MN Department of Transportation has complied with BTSAC permitting requirements
  • County Highway Departments have complied with BTSAC permitting requirements
  • BdSWD has experienced successful 103E project outcomes and positive feedback
  • BTSAC surface water design guidance is for small watershed only, not for river crossings
  • BWSR Clean Water funds are needed (“clean water” and “BTSAC” retrofit projects are

done concurrently)

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THANK YOU!

QUESTIONS?