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Impact 4.13-3 The proposed "restoration" of Tracy Lakes would greatly reduce or eliminate the water bird habitat value of two thirds of this historic seasonal wetland site. The excavation of all of North Tracy Lake and approximately half of South Tracy Lake would convert the present seasonal wetland habitats to relatively deep (15 to 25 feet),steep-sided small reservoir lakes. This proposed plan is not a restoration but a major habitat replacement which would result in the destruction of one of the best known natural wetland basins in the Central Valley. It would result not only in the loss of winter foraging and refuge habitat, but also habitat for spring and summer nesting activities and the rearing of young water birds. The main reason for this lies in the fact that the great majority of duck species that utilize the lakes are those which forage by "tipping up" in the water as opposed to diving. The functional foraging depth for these birds is the distance between the legs and billtips, or about one to two feet. Extensive shallow water zones are also crucial for a number of wading water birds such as herons, egrets, a large variety of large shorebirds, and the threatened greater sandhill crane. All of these species require an extensive shallow inshore zone with a rich complement of vegetation for survival. Even the several diving duck species which utilize these lakes require relatively shallow foraging depths(three to eight feet)as opposed to the deeper proposed depths. The applicant's management plan calls for the creation of a shallow water habitat in the eastern one-half of South Tracy Lake in order to offset the loss of shallow inshore habitat that presently exists naturally around both lakes. There are two biological problems with this proposed plan: 1) the respective areas involved are not equal; and 2) the progressive drying of these seasonal wetlands eventually produces a seasonal shallow zone which periodically covers approximately four-fifths of the total area of both lakes. Furthermore, the natural shallow zones are seasonal, providing a far more lush crop of vegetation on which dabbling ducks can forage as opposed to a permanent shallow area. Indeed,a heavy concentration of waterfowl in just the eastern half of South Tracy Lake would rapidly deplete available forage. Creating two islands in the deeper portion of South Tracy Lake reduces the available aquatic feeding area for the vast majority of wintering waterfowl. This also reduces the useable portions of the lake from which ducks would normally move when disturbed and under the proposed plan they would most likely fly offsite when disturbed. Incorporation of the following mitigation measures would result in no net loss of wetland habitat on the project site. The actual surface water area on the site would remain the same or may actually be slightly increased with the deepening of North Tracy Lake. The loss of inshore water bird habitat in North Tracy Lake would be offset by its roll as a standby water source which would be used to fortify South Tracy Lake during low rainfall years, thus insuring that this critical water bird habitat persists, even under drought conditions. This would be a better wetlands situation than occurred during the six-year drought period where a drastic loss of wetlands in both lake basins occurred. Mitigation Measures 4.13-3(a) Preserve the entire South Tracy Lake system in its present, unmodified state. 28