Introduction

1. Mitigation, Adaptive Management, and Lessons Learned at the Cow Creek Stream Restoration and StreambankStablization Project, Year 1 S.B. Lovern1*, G.A. Fox1, D.M. Maronek2, R.A. Chàvez1, R.B. Miller1 Departments of 1Biosystems and Agricultural Engineering and 2Horticulture and Landscape Architecture *Corresponding author: 214C Agricultural Hall, Stillwater, OK 74078, 405-744-5427, sharla.lovern@okstate.edu Oklahoma State University Research Supported by EPA ARRA Green Project Funds, OWRB CWSRF Contract ORF-09-0032-CW, OCC Water Quality Division Introduction Mitigation Adaptive Management • The primary adaptive management actions in 2012 have been: • Signage to establish mowing boundaries installed August ‘12 • Irrigation utilized to assist temporary cover of green sprangletop to survive on 3:1 slope, and other regions of drought-stricken vegetation • Herbicide for bermuda grass and other grass weed species sprayed near project boundaries • Small volunteer efforts to manage weeds • Employee and volunteers to plant additional container-grown natives and native seed in areas lacking growth The Cow Creek Project sought a green and sustainable solution to the problem of stream bed and streambank erosion along a riparian reach adjacent to the Oklahoma State University Botanic Garden property. Funds to support this project were secured from the American Recovery and Reinvestment Act (ARRA) Green Project Funds, awarded through the Oklahoma Water Resources Board Oklahoma Clean Water State Revolving Fund Progam, administered by the Oklahoma Conservation Commisssion, and expended and implemented by Oklahoma State University using existing and new contracts, and OSU personnel to direct and monitor. The primary mitigation activities were: (1) the fill and relocation of portions of the channel, (2) the installation of in-stream structures and altered morphology of the channel banks, (3) the relocation and enlargement of a floodplain swale, (4) the creation of a backwater constructed wetland for polishing of daily WTP lagoon discharge and stormwater flows from East agricultural fields, and (5) the removal and replacement of riparian vegetation. Non-woody plant performance standard: Vegetative stand establishment was assessed in consultation with NRCS Range Management Specialists. An average of 3 plants per square foot was calculated using a transect/quadrat analysis method. Woody plant performance standard: Achieve a stems per acre count for native reforestation of greater than 300 individuals of native species surviving after 5 years. 134 native species have been identified on-site thus far, with a count of 15,041 woody stems over 8.5 disturbed acres and thus approximately 1770 woody stems per acre surviving after 1 year. Many are elms and cottonwoods that were not intentionally planted but conditions were made favorable to their establishment. Approximately 600 stems per acre were in the supplemental planting plan. • Initial efforts to assess self-healing erosional areas vs. those that need assistance • Review woody stem numbers along shoreline to ensure canopy analysis has a good chance to improve in future years. • Wetland performance standard: By the end of the 3rd year, 20% plant coverage for the open-water-surface-area portion will be achieved along with a minimum of 80% coverage on the embankments. Also, no one species should constitute more than 25% of the plant totals. Re-planting of embankments will occur November ‘12 and invasive weed Cyperusdifformishas been identified and seed heads harvested; it is hoped that this species will not survive the winter and monitoring for diversity concerns and this species will continue. Harvesting of species may also be necessary to ensure sufficient open space on wetland surface. Timeline and Background The primary erosion-prevention goals of the project were the following: Stabilize the existing bank along the large project meander bend through OSU property; Prevent excessive and human-accelerated erosion (decrease total erosion) of the banks along the channel throughout the reach; use native species for above-ground and below-ground soil protection and stabilization; Increase flow area, flood storage, infiltration, and energy dissipation. 2011 2012 Before After Before 82% 35% • 5/09: Project proposal submitted • 7/09-11/09: Plan development and review • 11/09: Initiation of Clean Water Act Sections 404 & 401 permitting process (also FEMA & Earth Change) • 12/09: Construction Manager at Risk (CMAR) hired • 1/10: Planning for pre-construction monitoring begins • 10/09 and 1/10: ODOT rip-rap removal at Highway 51 reduces ponding of project; • 12/09: Construction Manager at Risk (CMAR) hired • 3/11: Bid package for custom grown plants issued • 8/11: Mobilization and beginning of construction • 9/11: Irrigation plan developed • 9/11-10/11: Expert visit on-site review, engineering drawing modifications for slope changes • 10/11-2/12: Many meetings to discuss soil erosion and sediment control material, installation protocol with seed, and post-rainfall event damage review and fixes • 12/11: Expert visit on-site review, engineering drawing modifications for in-stream structure numbers, types, and locations • 1/12-2/12: Installation of plants • 2/12-3/12: Continued erosion damage discussions and fixes • 2/12: Cow Creek project declared substantially complete for earthwork and vegetation sub-contractor, punch list walk around and implementation • 3/12: Final punch-list review meeting for earthwork and vegetation sub-contractor • 4/14/12: High-intensity rain event • 5/12: Repair of 3:1 slope surface erosion by CMAR after re-direction of stormwater runoff, de-mobilization of CMAR • 8/12-present: Adaptive management begins -- irrigation initiated, signage installation to prevent mowing of easement area (signage planning began 2/12), manual removal of nuisance species, additional seeding and planting • 11/12: First annual report submitted to USACE and ODEQ, 5 years to complete mitigation Red Rock Consulting, LLC – Edmond, OK Additional soil types represented: sandy lean clay (med stiff to very stiff), silty clayey sand (loose), sandy lean clay (soft), clayey sand (very loose), lean clay with sand (very soft to soft), sandy silty clay (soft), sandy lean clay (med stiff) After • Pedestrian bridge safety improved • Slight stream alignment shift when outer meander slope built out • Constructed cross-vane, rock riffle and several J-hooks located upstream of the bridge to pull the energy off the bank and back to the center of the stream • Native species replace introduced species Before/After Pictures: Utility pole visible in both -- slope was built out away from infrastructure and the channel slightly shifted towards the photographer to allow for shallower slopes and good vegetation growth. Lessons Learned Year 2 • Native vegetation often requires custom grown contracts, contracts need to begin 1-2 years in advance of plant installation to obtain seed source, properly condition the seed, and allow for appropriate plant growth conditions and environmental timing. • Soil erosion and sediment control materials must be installed in a moist-soil condition to obtain appropriate integration between the product and the soil. If the materials are too tightly stretched or integration does not occur, the material will be undermined from surface runoff or fluvial flow. The material must also be staked in a pattern designed to prevent lift of the material from vegetative growth and fluvial flow. • Ensure that an adaptive management team (vegetation experts and engineers) is in place to ensure that native vegetation survives, and erosion locations are managed, in the initial 2 years until native vegetation starts thriving and becomes self-sustaining. • Native plants are not expected to fully establish during the first year and the native seed presence in the soil is expected to express itself over the next several years. • Storm events are expected in 2013 that will be sufficient to improve flow monitoring record, and erosion conditions measurable by terrestrial LiDAR, bank erosion pins, and cross-sectional surveys. • Blue Thumb volunteer monitoring will continue to add information to the OCC biological and habitat monitoring record conducted once pre-construction and once post-construction. RAINFALL EVENTS Greater than 1” 9/22/2011: 1.25” 10/9/2011: 1.38” 11/7/2011: 1.08” 12/19/2011: 1.03” 2/3/2012: 2.22” 3/19/12: 1.56” 4/11/12: 1.56” 4/14/12: 2.71” 6/15/12: 1.21” 8/25/12 1.88” Invasive non-native Cyperusdifformis • Hold a separate pre-project meeting with all contractors and SESC manufacturer’s representatives to review SESC plan (including materials and methods of installation) and prepare contingency plans for bad weather and other delays in erosion control plan. In Oklahoma, expect high-intensity rains and be prepared for intense surface runoff. • More information: • http://biosystems.okstate.edu/home/sharlbl/CowCreekAddendum • Scan the following code and then click on label “Cow Creek Restoration”