Multipurpose Drainage Management – and Storage Red River Basin Drainage Conference Moorhead, MN 3-19-19 Al Kean, Chief Engineer, BWSR | bwsr.state.mn.us
Outline Topics to Consider: 1. What does Multipurpose Water and Drainage Management mean? 2. Key descriptors of Minnesota hydrology 3. Needs for multipurpose water / drainage management 4. Types and scales of storage and multipurpose water management 2
Important Understandings 1) MN has good process for Local Water Planning and implementation; current approach = One Watershed, One Plan 2) Local Water Planning is about Multipurpose Water Management 3) Where there is much drainage, Multipurpose Water Management must include Multipurpose Drainage Management 4) Chapter 103E Drainage law is not water planning law - - but: a) increasing compatibility with multipurpose local water planning and 1W1P - - however, drainage systems must choose to use b) helped by stakeholder Drainage Work Group recommendations 3
MN Drainage Law, Section 103E.015 – 2014 Update Section 103E.015 CONSIDERATIONS BEFORE DRAINAGE WORK IS DONE, Subd. 1. Environmental, land use, and multipurpose water management criteria. Before establishing a drainage project, the drainage authority must consider each of the following criteria: ( Note: there are 9 criteria) (2) alternative measures, including measures identified in applicable state-approved and locally adopted water management plans, to: (i) conserve, allocate, and use drainage waters for agriculture, stream flow augmentation, or other beneficial uses; (ii) reduce downstream peak flows and flooding; (iii) provide adequate drainage system capacity; (iv) reduce erosion and sedimentation; and (v) protect or improve water quality; 4
MN Drainage Law, Section 103E.015 – 2014 Update Section 103E.015 CONSIDERATIONS BEFORE DRAINAGE WORK IS DONE, Subd. 1a. Investigating potential use of external sources of funding and technical assistance. • Refers to Section 103E.011 DRAINAGE AUTHORITY POWERS. , Subd. 5. Using external sources of funding. (for wetland restoration, WQ, or flood control) • Requires drainage authority investigation of external sources of funding for the purposes in 103E.011, Subd. 5 and “alternative measures” in Subd. 1, clause (2) • Includes requirement for early coordination with SWCD, County and WD water planning authorities • Applies to “drainage projects” and petitioned repairs, all of which require an engineer’s report 5
Hydrologic Cycle – Water Mass Balance Statewide condensation across Minnesota: • About 50% - 90% of precip. recycles as evapotranspiration • About 10% - 50% of precip. is runoff recycled as ET or deep infiltration downstream surface and subsurface • Statewide ave. 2% of precip. goes to deep groundwater Source: Climate of MN, Part XII – The Hydrologic Cycle and Soil Water , D.G. Baker. et al., UMN Technical Bulletin 322, 1979 6
Minnesota Average Annual Precipitation 1981 - 2010 Average annual precipitation varies substantially northwest to southeast (21 to 36 inches) Source: MN Climatology Office 7
Minnesota Average Annual Runoff 1971 - 2000 Average annual runoff varies substantially – west to east (3 to 16 inches) About 3 to 5 inches in the Red River Basin Source: MN Climatology Office 8
Minnesota Runoff as % of Precipitation 1971 - 2000 Average relative runoff (10% to 50% of precipitation) Source: MN Climatology Office Runoff Coefficient or Runoff Ratio = relative runoff as a decimal number (0.1 to 0.5 for MN 1971-2000) 9
MN Annual Precipitation Change (%): 1946-1965 to 1986-2005 Average Annual Precip. Increase by Watershed (0 to 16%) Source: “Annual Stream Runoff and Climate in Minnesota’s River Basins” , Todd R. Vandegrift and Heinz G. Stefan, UMN SAFHL, September 2010 Climate Change – No matter the cause(s), on the ground responses need to be the same – multipurpose water management. 10
MN Ave. Annual Runoff Change (%): 1946-1965 to 1986-2005 Runoff has generally increased in recent decades (up to 35%) Source: “Annual Stream Runoff and Climate in Minnesota’s River Basins” , Todd R. Vandegrift and Heinz G. Stefan, UMN SAFHL, September 2010 11
Increased Runoff Coefficient – Red River Basin Runoff Coefficient = Runoff ÷ Precipitation Change in Runoff Coefficient is one good indicator of Altered Hydrology (AH) Source: “Annual Stream Runoff and Climate in Minnesota’s River Basins” , Todd R. Vandegrift and Heinz G. Stefan, UMN SAFHL, September 2010 12
Increased Runoff Coefficient – Minnesota River Basin Runoff Coefficient = Runoff ÷ Precipitation Change in Runoff Coefficient is a one good indicator of Altered Hydrology (AH) Source: “Annual Stream Runoff and Climate in Minnesota’s River Basins” , Todd R. Vandegrift and Heinz G. Stefan, UMN SAFHL, September 2010 13
Red River Basin Reasons for Multipurpose Drainage Mgmt. Flood Damage Reduction (FDR) Red River Basin 45,000 sq. mi. 20% in Canada ̴ 40% in MN ̴ 40% in ND 14
Red River Basin Reasons for Multipurpose Drainage Mgmt. Flood Damage Reduction (FDR) 2 nd St. N., Fargo, ND, 3-28-09 Halstad, MN, 4-13-11 15
Red River Basin Reasons for Multipurpose Drainage Mgmt. Natural Resource Enhancement (NRE) North Ottawa Impoundment, BdSWD Grand Marais Creek Outlet Restoration, RLWD 16
Red River Basin Reasons for Multipurpose Drainage Mgmt. Water Quality Lake Winnipeg (9,500 mi. 2 ) Red River Basin contributes 68% of P 34% of N Most during spring runoff Source: Nutrient Loading to Lake Winnipeg, gov.mb.ca 17
Red River Basin Reasons for Multipurpose Drainage Mgmt. Water Quality Minnesota Impaired Waters 2018 Primary impairments in Red River Basin: • Total Suspended Solids (TSS) • Turbidity • Dissolved Oxygen (DO) Source: MPCA MN Nutrient Reduction Strategy, 2014 goals for Red River Basin / Lake Winnipeg: P = 10% reduction from 2003 conditions N = 13% reduction from 2003 conditions 18
Primary Methods for Multipurpose Water Mgmt. • Runoff hydrology management (rate, timing and volume) typically to reduce peak flows and/or volume of runoff; can involve storage, land use, infiltration, evapotranspiration • Erosion reduction practices and designs (typically including some storage and treatment) • Gravitational and biological treatment of runoff (e.g. sediment settling, vegetation / crop use of nutrients, microbial and bacterial action) 19
Two Fundamental Ways to “Improve” Drainage Runoff Hydrology Management • Increase the size and capacity of a drainage system (public and/or private) • Reduce the demand on the drainage system (detention and/or retention storage and increased evapotranspiration) • Various types and scales of detention and retention storage • Includes practices that increase evapotranspiration and thereby decrease runoff 20
Runoff Timing – Early, Middle, Late Map depicts early, middle and late areas relative to the mainstem of the Red River (basin scale) Source: TSAC Technical Paper No. 11, Red River Basin Flood Damage Reduction Framework, May 2004 Also consider timing effects at the watershed and subwatershed scales 21
Greater Blue Earth River Basin CSSR – Sediment Load vs. Flow The “Hockey Stick” relationship Source: CSSR: Collaborative for Sediment Source Reduction Greater Blue Earth River Basin Final Report 31 October 2016 Figure 6.6: Sediment loading from NCSs in the incised zone normalized by the mainstem river length as a function of river discharge normalized by the upstream drainage area shows that sediment loading responds to peak river discharge, particularly when the river discharge exceed the threshold point marked by the red dotted line. (NCS = Near Channel Sources) 22
Key Finding – Greater Blue Earth River Basin CSSR • Achieving water quality goals will require priority investment in more temporary water storage to reduce high tributary river flows and bluff erosion. This is a critical component of a strategy to reduce sediment in the Minnesota River. Note: 1) Shouldn’t forget that Streambank, Bluff and Ravine erosion are major erosion sources in the GBERB, but upland erosion is still a large volume 2) Storage in the uplands for erosion control, WQ and FDR is multipurpose 23
RRB Topography Primary Sources of Erosion and Sediment in the RRB: • Glacial Lake Agassiz beach ridges (streambank, bluff, ravine) • Field sheet and rill erosion • Field wind erosion • Rivers, streams and coulees Map Source: International Water Institute (IWI) 24
Storage & Multipurpose Water Management at Different Scales 25
“Storage” Related Terminology and Scales • “Detention” (short-term) storage: timescale typically = hours or days • “Retention” (longer-term) storage: timescale typically = weeks or months • “Temporary” storage: typically means detention, but can mean retention • “Permanent” storage: also called “normal pool” • “Reservoir”, “Impoundment”, “Basin”, “Pond”, “Pool” (scale) • “Dam”, “Embankment”, “Berm”, “Dike” (scale) • “Principal” Spillway or Outlet • “Auxiliary” or “Emergency” Spillway or Outlet • Scales: field, farm/property, subwatershed, watershed 26
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