Baby Bottle Pond Invasive Species Eradication Project

The project will drain the pond to remove largemouth bass and invasive species such as bullfrogs from the pond. Aquatic vegetation will be removed from a small section of the pond to improve sensitive species habitat. Introduction The East Bay Municipal Utility District (EBMUD) manages 29,000 acres of undeveloped land in Alameda and Contra Costa Counties. EBMUD properties are managed under the Low Effect East Bay Habitat Conservation Plan (HCP) established in 2008. The HCP outlines long term management goals for livestock pond maintenance and invasive species removal to conserve special status species. Western pond turtle (Actinemys marmorata) and California red-legged frog (Rana draytonil) populations are monitored by EBMUD staff to ensure that habitat goals are met. The western pond turtle has been proposed for listing as threatened by the U.S. Fish and Wildlife Service (USFWS). The California red-legged frog is listed as federally threatened. Both species are listed as California Species of Special Concern by the California Department of Fish and Wildlife (CDFW). In May 2026, four largemouth bass (Micropterus nigricans} were found by EBMUD staff in Baby Bottle Pond (#85) during western pond turtle surveys. The bass were caught in a hoop trap along the pond perimeter and were culled. The bass had fork lengths between 210 - 270mm. These fish were likely illegally planted in the pond by rogue fishermen. The pond mostly dried in fall of 2021 during an extreme drought, and the fish were likely planted after the pond refilled. Although only four individuals were captured, additional fish are likely present within the dense emergent vegetation within the pond. Because the pond is typically perennial and supported by a reliable spring source, non-native fish could persist indefinitely without intervention. Bass, other non-native fish, and American Bullfrogs (Lithobates catesbeianus) are known to prey upon and out-compete native aquatic species. Early eradication is warranted to prevent reproduction and expansion of non-native populations. Removal of non-natives is consistent with the California Red-Legged Frog Recovery Plan, which identifies introduced predatory fish and bullfrogs as significant threats to California red-legged frog populations and recommends eradication as a habitat restoration strategy where feasible. The purpose of this project is to restore and enhance aquatic habitat conditions at Baby Bottle Pond by eliminating non-natives and improving shallow-water habitat for native amphibians and western pond turtles. The project is intended to increase habitat suitability for California red-legged frogs, western pond turtles, and other native aquatic species by removing a documented source of predation and competition and by increasing the availability of drought-resilient breeding and foraging habitat. EBMUD is seeking coverage under the State Water Board's general certification for small habitat restoration projects (Order No. WQ 2022-0048-DWQ) and is applying for a California Department of Fish and Wildlife (CDFW) Habitat Restoration and Enhancement Act (HREA) permit. EBMUD staff consulted with CDFW on June 4, 2026, and determined that the HREA permitting pathway is appropriate due to the project's limited footprint (less than 1.5 acres) and its primary objective of restoring and enhancing habitat for native wildlife species. Federal incidental take will be covered under EBMUD's HCP (TE 183192-0). The project is proposed to begin in mid-September 2026 and last three weeks. The project will have a monitoring and adaptive management period of 5 years. General Project Description The pond will be drained over the course of two weeks. The pond will be drawn down using a gravity fed siphon the first week. Clean water diverted from the pond with a siphon will be allowed to flow down the drainage connected to the pond where the current culvert outflow spills. The siphon will be monitored to ensure only clear water flows downstream. A significant drop in vertical elevation (fall) is required downslope of the pond for the gravity siphon to operate. This is the only location with enough fall for a siphon to function. The intake of the siphon will be screened (minimum 1/8-inch mesh size) to prevent tadpole or fish entrainment and impingement. Erosion control measures will be placed in the drainage at the siphon outfall to mitigate erosion or sediment transport. The flow rate of the 2-inch siphon is estimated to be between 10 -25 gallons per minute (gpm), depending on head pressure. The siphon outfall will be checked daily during draw down to confirm erosion is limited. Two siphons may run in tandem to achieve sufficient draw down if needed. Once the pond is drained to a depth of 2 to 3 feet, the remaining water will be pumped from the pond to an upland location. Pumping may also occur during the first week of draining if pond draw-down by siphon is not sufficient to reduce water levels. Pumped water will be released onto visqueen and filtered through straw and gravel before flowing towards the water course. The pump outfall and water filtration area may be adjusted to minimize downslope impacts or roadside pooling. Sediment laden water will not enter the stream channel. Pump intakes will be screened with 1/8-in hardware cloth or stainless-steel mesh. Two pumps may run in tandem to achieve sufficient draw down if needed. The maximum pump flow rate is 82 gpm. The electric pumps will be plugged into a gas-powered generator. The generator will be operated on the fire road with a fire blanket underneath. An oil absorption pad will be placed under the generator during gas refills and extra oil absorbent pads and booms will- be on site as an extra precaution. Once the pond is mostly dried, invasive fish and bullfrogs will be seined, netted and culled. After the pond is drained, EBMUD will remove less than a quarter of the vegetated perimeter (up to 0.2 acres) using a long-reach excavator to increase open shallow water habitat and support frog and turtle populations during drought years. The excavator will access the pond via the Baby Bottle Fire Road which runs alongside the eastern perimeter of the pond. As vegetation is removed from the pond using a clamshell or bucket attachment, it will be piled on the hillside on the opposite side of the fire road and allowed to dry before it is off hauled. The excavator will not travel further than 10 feet from the margin of the fire road to reach the pond or stockpile area. A biologist will be present observing each bucket of excavated material as it is removed and another biologist will observe the stockpile. The stockpile area is estimated to be up to 0.13 acres. A map of the area of vegetation removal, access route, siphon outfall location, tentative pump outfall location, water filtration area and stock piling area is shown in Figure 2. To avoid the potential for western pond turtle nest impacts, all vegetation removal will occur below the high-water line of the pond where saturation levels are too high for nest deposition. Ground disturbance in upland areas is not expected to occur. However, stockpiled material will be placed in upland habitat suitable for turtle nesting. Stockpiled material will be placed on the hillside while the equipment is staged on the fire road using the reach of the excavator arm. Vegetation will be off hauled using a clam shell bucket or a bucket with a knuckle attachment so as not to scrape the ground surface and to avoid nest exposure. Project Timeline The initial pond draining, non-native species eradication and vegetation removal work is tentatively planned to occur in mid-September 2026. Project performance monitoring will occur between September 2026 and September 2030. Permits shall cover a 5-year term in case follow-up draining is needed to adaptively manage non-native species populations. Please see the attachment for details regarding the Description of the Project Area, Project Timeline, Wildlife Holding and Translocation Plan, Monitoring Plan, Best Management Practices, and Project Site Photos.