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Biological Resources <br />Long-term operation of the proposed courthouse facility may adversely affect fish by increasing <br />stormwater discharge from impervious surfaces, reducing ground water recharge, and degrading <br />water quality. A net increase in the amount of impervious surface area may increase the <br />frequency of events and the volume of stormwater that discharges into fish habitat, thereby <br />displacing juveniles downstream. A net increase in the amount of impervious surface area can <br />also reduce ground water recharge, affecting juvenile fish during the summer low-flow period. <br />Stormwater runoff can degrade water quality and harm fish by increasing water temperatures and <br />by transporting pollutants such as petroleum hydrocarbons. <br />Alternative 1, Options A and B <br />Because the Riverfront site is urbanized and has previously been developed, project impacts on <br />biological resources would be minimal, primarily consisting of the loss of trees. There are 15 <br />existing trees within the preliminary building footprint shown on the Alternative 1 site <br />(Figure 6). The removal of several trees under this alternative would not result in a significant <br />adverse impact on the biological resources of this area. <br />Habitat for threatened and endangered fish species in the Willamette River may be affected <br />during construction of the proposed courthouse facility at the Riverfront site, based on the <br />impacts described previously. This site is located within 25 feet of a side channel slough <br />connected to the Willamette River, and stormwater drains on the site discharge directly into the <br />river. Stormwater runoff during construction has the potential to affect fish habitat in the <br />Willamette River downstream of the site. Because this site is already covered with impervious <br />surfaces, the long-term operation of the courthouse on the site should not increase stormwater <br />discharge or reduce ground water recharge. <br />Alternative 2, Option A (Preferred Alternative) and Option B <br />'' The Chiquita site (formerly Agripac) is urbanized and has previously been developed. Because <br />~: <br />this site is already covered with impervious surfaces, the long-term operation of the courthouse <br />on the site should not increase stormwater discharge or reduce ground water recharge. There are <br />no trees within the preliminary building footprint shown on the site (see Figure 6). <br />Habitat for threatened and endangered fish species in the Willamette River is not likely to be <br />affected during construction of the proposed courthouse facility on the Chiquita site, because the <br />site is located approximately 350 feet away from the Willamette River, although storm drain <br />pipes on the site discharge directly into the river. Moreover, the Southern Pacific Railroad tracks <br />prevent overland flow of stormwater between the site and the river. Consequently, the proposed <br />project would have no impact on biological resources at this site. <br />No-Action Alternative <br />Biological resources would not be affected by the no-action alternative. <br />New Federal Courthouse 59 Final EIS <br />