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3. Environmental Checklist San Leandro Treatment Wetland IS/MND 3-22 February 2024 connected to, and receives flow from, a river or stream. Observations of upstream conditions were made, supported by the review of available documentation, to verify whether the engineered tidal channel that runs through San Leandro's WPCP connects to a river or stream. In the late 1990s, Alameda County's stormwater program sponsored a project to develop a Creek & Watershed Map of Hayward & San Leandro.21 This map stemmed from an extended initiative of the Oakland Museum of California to create a Guide to San Francisco Bay Area Creeks, the data for which is hosted on Oakland Museum of California's website. Information used in that project included the historical ecology of regional watersheds and stormwater infrastructure, given the conversion of most urban creeks in the region to engineered stormwater channels and underground culverts. Figure 3-1 provides a detail view of the Project location and the channel in question, from the Creek & Watershed Map of Hayward & San Leandro. The figure shows the engineered channel that runs north- south within the San Leandro WPCP to be isolated from any stream or river, including San Leandro Creek. Figure 3-1. Detail view of the Creek and Watershed Map of Hayward and San Leandro, showing the Project location and the tidal channel in question. The engineered channel (solid red line) is connected to underground culverts and storm drains (dashed lines) without connectivity to a stream or river, including San Leandro Creek. The engineered channel meets San Francisco Bay at the southeast corner of the basin under consideration for conversion to a treatment wetland. This channel flows through the Metropolitan Golf Links, formerly known as the Lew Galbraith Golf Course – created from a dredged materials disposal area. Based on historical aerial imagery, retention basins were constructed within the golf course between the years 2000 and 2002. Based on communications with golf course management, the retention basins are filled with well water and used for irrigation. The pre-existing channel that flowed through the golf course was culverted and connected to a retention pond along the northern perimeter of the golf course. Alameda County Flood Control District maintains the pond, which is fed with municipal stormwater. During the wet season, stormwater is routed from the detention basin under the golf course and to the tidally influenced engineered 21 Sowers, J. Creek & Watershed Map of Hayward & San Leandro; Guide to San Francisco Bay Area Creeks; The Oakland Museum of California: Oakland, CA, 1996. Available at http://explore.museumca.org/creeks/MapHay.html