Appendix A Natural Environment Study (Minimal Impacts)

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JURISDICTIONAL DELINEATION REPORT FAIRVIEW STREET IMPROVEMENTS A N OVEMBER 2018 FROM 9TH STREET TO 16TH STREET AND BRIDGE REPLACEMENT PROJECT `J" SANTA ANA, CALIFORNIA RESULTS Based on close examination of historical and recent aerial photography and fieldwork, the consultant biologists identified one major drainage feature occurring in the Jurisdictional Delineation Limits (i.e. the Santa Ana River). Site -specific conditions and channel measurements were collected and the drainage feature was mapped. Within the Jurisdictional Delineation Limits is the Fairview bridge, a continuous nine span bridge with reinforced concrete pier walls (see Figure 3 Representative Site Photos). The Santa Ana River conveys an intermittent flow under the bridge and is concrete lined within the Jurisdictional Delineation Limits. The channel bed is 180 feet wide and in the center of the channel is a linear low flow concave channel. The banks are 41 feet in height on the east and the west sides. The tops of the banks are earthen or asphalt and make up the Santa Ana River trail. The Santa Ana River channel is entirely devoid of vegetation within the Jurisdictional Delineation Limits. The vegetation at the top of the banks is ornamental and appears to be regularly maintained along the Santa Ana River trail system. No other jurisdictional features were identified within the Jurisdictional Delineation Limits. No sample point was dug; the entire section of the Santa Ana River within the Jurisdictional Delineation Limits is lined with concrete. UNITED STATES ARMY CORPS OF ENGINEERS JURISDICTION Non -Wetland Waters of the United States The Santa Ana River within the Jurisdictional Delineation Limits is a concrete -lined intermittent drainage feature. This drainage conveys flows attributed to local urban runoff and from seasonal storms. The low -flow channel located within the center of the channel bed had standing water at the time of the survey. The Santa Ana River contained an OHWM that was determined to be 21 feet up from the channel bed. Three measurements were taken within the trapezoidal channel of the Santa Ana River to determine the OHWM. The first measurement was from the toe -of -slope to the edge of the bike path under the bridge (19 ft), the second measurement was from the toe -of -slope to the horizontal terrace located up the bank (27.2 ft), and the third measurement was from the toe -of slope to the top of bank (43.2 ft). Using the three measurements and Google Earth historical imagery, the OHWM was determined to be 21 ft. The river has a direct nexus to the Pacific Ocean, a navigable water of the U.S., and is tidally influenced at its mouth. However, the tidal influence does not extend to the Jurisdictional Delineation Limits, and there are no waters subject to jurisdiction under Section 10 of the RHA. No wetlands were identified within the Jurisdictional Delineation Limits. CALIFORNIA DEPARTMENT OF FISH AND WILDLIFE JURISDICTION Jurisdictional Streambeds This intermittent concrete -lined drainage feature is defined by the presence of a channel bed and bank, and therefore, CDFW would consider the entire feature to the top of the bank to be jurisdictional. \\vcorp12\projects\WKE1702\N ES- MI\November 2018 Sub mittal\Fairview Street I m proveme nts_Draft JD 110918.docx all/09/18» 11