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North Fork, Gunnison River Ecosystem Restoration <br />Appendix B: Engineering Appendix March 2005 <br />6.1.3 Boulder Structures <br />J-hooks, cross vanes, and random boulder clusters aze common to most of the sites within this <br />project. The placement of these structures will vary from site to site depending upon [he energy <br />gradient and individual objectives. <br />6.1.4 Irrigation Diversions <br />Reconstruction of irrigation diversions are components in four of the nine sites. Common <br />objectives include the delivery of a full decree of irrigation water while eliminating the need for <br />annual bulldozing in the channel, migration of fish and habitat enhancement. NFRTA has <br />successfully completed four irrigation diversion reconstruction projects on [he North Fork, <br />including the Monitor ditch diversion at Site 6, since 1999. Designs for this 206 project will be <br />similar in nature and unit costs are based upon average actual costs recently incurted. <br />6.1.5 Floodplain Revegetation <br />In addition to bank revegetation, many sites have large areas of floodplain revegetation associated <br />with them. Designs for these areas include the placement of topsoil over the cobble and gravel <br />substrate. Seeding, willow installation and general revegetation will take place in [he late autumn <br />during [he plant dormant season. A biodegradable netting will be installed over the topsoil <br />following seeding to reduce erosion. <br />Energy dissipating log fences are another erosion and sediment control technique developed for <br />this project. The idea behind energy-dissipating log fences is to slow down overbank flooding to <br />prevent channel avulsion and naturally deposit debris and sediment along recently gaded fill <br />areas [ha[ are devoid of vegetation. Flood waters from the North Fork are loaded with native <br />seeds and if given the chance will germinate naturally on their own. The structures can be <br />constructed with dead cottonwood trees currently found close-by in [he floodplain and a few well <br />placed boulders. This technique has no[ been used previously on the North Fork. <br />6.1.6 Irrigation and Wastewater Management <br />Many of the sites with proposed revegetation will also require temporary irrigation to plant and <br />seed material. Much of [he land adjacent to these sites is irrigated farmland and it is proposed [o <br />pipe the wastewater from these fields temporarily to the floodplain revegetation sites. Gated pipe <br />will be laid out in these areas for irtigation during the growing season. NFRIA will be responsible <br />for the operation and maintenance of the irrigation systems. Legal council will be sought during <br />feasibility to insure the temporary irrigation proposed is in conformance with all state water laws. <br />6.1,7 Monitoring and Adaptive Management Plan <br />A monitoring and adaptive management program shall be developed and implemented after <br />construction for aspects of the project such as: riparian plantings, and in channel structures. = ~ -' <br />Monitoring and adaptive management has been determined to be an essential element in the ~ ~ ~ -~ - . - <br />overall implementation of the proposed restoration plan since it provides an opportunity to review ~'~ - <br />and evaluate the performance ofthe project, after construction is complete, and implement minor • ~ ~~ <br />revisions to the overall project based upon evaluations. This covers monitoring and adaptive <br />management actions during the firs[ five years after initial construction. <br />B-30 <br />