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<br />002724 <br /> <br />Opportunities for Ecological Improvement Along the Lower Colorado River <br />Mark Briggs and Steve Cornelius <br />7/24/97 <br /> <br />Site #6 <br />Three-Finger Lake <br />Location and Size:. The 50 hectare site is located in the Cibola National Wildlife Refuge <br />on the western side of the river due north of Paymaster Landing. <br />Objective: To restore Three-Finger Lake to its pre-1970 condition. <br />Completion Date: To be completed during 1998. <br />Pre-Project Site Conditions:. Depending on Colorado River flow, the size of Three- <br />Finger Lake historically ranged from eight to 60 hectares (150 acres). In 1970, <br />channelization and realignment of the Cibola Division of the river was completed, <br />diverting waters away from Three-Finger Lake and the old river channel. Saltcedar <br />invaded as the lake dried and wildfires eliminated most of the native vegetation. <br />Today, the site was dominated by a dense monotypic stand of saltcedar. <br />Project Strategy: Beginning in 1994, approximately 50 hectares (127 acres) of the lake <br />site was dredged to an elevation of 65 m (212 ft). In addition, one fish pond was <br />created for rearing native fish. Native riparian vegetation will be planted around the <br />dredged areas. <br />Results: [the project is scheduled to be completed during 1997] <br /> <br />Site #7 <br />Imperial Refuge Cottonwood and Willow Revegetation Site <br />Location and Size: This 15 hectare (six-acre) site lies within the Imperial National <br />Wildlife Refuge, which is located near Martinez Lake, Arizona. <br />Objective: To re-establish Fremont cottonwood and Goodding willow in an area heavily <br />modified by agriculture pressures and overrun by saltcedar. <br />Completion Date: 1995 <br />Pre-Project Site Conditions Wheat and rye were once cultivated on this site. Since <br />abandoned, the fields were overrun by saltcedar, arrowweed, and other undesirable <br />species. <br />Project Strategy: Over 600 cottonwood and willow trees were planted in January of 1995. <br />Prior to planting, exotic plants (mainly saltcedar) were cleared from the site with a <br />bulldozer. Soil salinity investigations were performed to guide the development of the <br />planting design and two piezometers were installed to monitor water table <br />fluctuations. Cleared areas were then disked and leveled, and the site was flood <br />irrigated just before the onset of revegetation. An auger was used to drill to saturated <br />soils, which at the time of planting varied between 1 m to 2.5 m below the soil surface. <br />Holes were spaced six meters (20 feet) apart Poles collected from the Imperial Wildlife <br />Refuge's nursery were stripped of leaves and branches, and placed in the ground. The <br />average length of the poles used in the revegetation effort was 4 m and the average <br />diameter at breast height (dbh) was 3.0 em. Following planting, the site was flooded <br />monthly and plants received two liquid fertilizer applications during the growing <br /> <br />Page 12 <br />