Water control structures remain closed to protect sparrow nesting area

WEST PALM BEACH — On June 18, South Florida Water Management District Executive Director Drew Bartlett sent a letter to the U.S. Fish and Wildlife Service asking to open two water control structures early in order to address concerns about high water levels in the Water Conservation Areas (WCAs) south of Lake Okeechobee.

Larry Williams, FWS state supervisor, denied this request.

In the June 22 letter, Bartlett wrote, “As the non-federal sponsor of the Central & Southern Florida Project (C&SF), the South Florida Water Management District is keenly aware of the necessity to operate infrastructure in a way that is both protective and beneficial to the environment. All three Water Conservation Areas (WCA) are already above their regulation schedules, resulting in the rapid inundation of WCA 3A. District meteorologists predict this wet season will be a wetter-than-average wet season. Given that we are just entering the 2020 wet season, it is in the best interest of the environment to lower water levels now in the WCAs in preparation for the remainder of the wet season.

“Water levels in WCA 3A are approaching the increment 2 action line within the regulation schedule. Bearing in mind that June is only the beginning of the wet season, it is critical to mitigate higher water levels to avoid harmful ecological impact to native vegetation, apple snail reproduction and the health of remaining tree islands in the area. Lowering water levels in the WCAs below their regulation schedule would also allow Lake Okeechobee water deliveries if necessary to mitigate harmful estuary discharges.

“The district will begin to moderate ascension rates by installing temporary pumps at the S-151 structure to move water out of WCA 3A and into WCA 3B, and we are also exploring additional measures that can be taken to alleviate high water conditions in WCA 3A.

“One opportunity to alleviate high water conditions is to open the structures north of the Cape Sable seaside sparrow’s (CSSS) subpopulation A earlier than July 15th. This district requests that the U.S. Fish and Wildlife Service review available information and the length of the breeding season against the likelihood of impact to subpopulation A to determine if an early opening is possible.”

The response, dated June 29, denies the request to let the additional water flow south under the Tamiami Trail.

Williams wrote: “The service appreciates all the South Florida Water Management District’s efforts to manage water resources wisely and maintain healthy environments. We especially appreciate the district placing temporary pumps at the S-151 to help lower water levels in WCA-3A. As you know, we welcome the opportunity to collaborate with the district and other partners on water management decisions.

“The district requested the service review available information concerning Cape Sable seaside sparrows and their breeding season against the likelihood of impacting subpopulation A if water control structures were opened before the permitted date of July 15. The July 15 date is the permitted date, per the service’s July 22, 2016, Everglades Restoration Transition Plan (ERTP) Biological Opinion, whereby the S-12 A and B structures can normally be opened. That date was included in the Biological Opinion as a way of protecting sparrow nests and habitat from being flooded.

“The service issued the ERTP Biological Opinion to the U.S. Army Corps of Engineers because the corps is the action agency implementing ERTP. Therefore, authority to make any changes to ERTP and structure opening dates lies with the corps. The service’s role is to advise the corps in situations like this. According to ERTP the S-12 A and B structures can be opened before July 15 if the headwater stage is greater than 11.0 feet NGVD, to pass enough water to prevent overtopping of gates. The corps will assess upstream conditions and will close the gates when headwater levels drop below 10.75 feet NGVD. The current headwater stage for the S-12 A and B is 9.44 and 9.39 feet NGVD, respectively. Therefore, the corps cannot open the gates at this time according to ERTP. Just for context, the corps has calculated the benefit of opening the S-12 A and B structures 30 days early and that action would lower the stage in WCA-3A by approximately 2 inches in 30 days.

“In the past the corps requested a deviation to open the structures early when water levels neared a High Water Action Line which is 10.72 feet NGVD. As we understand, a deviation like this must be approved by the South Atlantic Division commander of the corps. Since the current stage of WCA-3A is 10.24 feet NGVD, we understand there are no current plans to request a deviation.

“A goal of ERTP and the upcoming Combined Operational Plan is to move water out of WCA-3A and into Shark River Slough by increasing the L-29 Canal stage to 8.5 feet. The L-29 canal is currently at 7.8 feet, so there is significant unused capacity there. We realize in recent weeks the S-333 could be operated only at night because of construction at the S-333N. However, as we understand, that construction will soon be done. Increasing the L-29 to 8.5 feet will move a bigger volume of water out of WCA-3A than would opening S-12 A and B. Therefore, we recommend increasing the L-29 to 8.5 feet before opening S-12 A and B.

“Due to COVID-19, biologists were unable to survey subpopulation A this year, therefore, we have no information specific to subpopulation A. However, biologists are monitoring other subpopulations. Nesting activity is still occurring in subpopulations B and D, so we believe there are active nests in subpopulation A. There is still dry habitat in all subpopulations, including A, and the percentage ranges from 24 to 50 percent of the areas. For these reasons, we believe opening the S-12 A and B structures now would likely flood active nests. Further, there have been two large wildfires (Guava, Moonfish) in subpopulation A since May 7. These fires burned some of the nesting habitat, but not all of it. National Park Service staff believe that flooding the burned areas now will encourage the plant community to shift toward sawgrass and sedges, and away from the Muhly grass community that sparrows need.

“Therefore, we have additional reasons to discourage opening S-12 A and B at this time. In addition, it’s worth noting National Park Service staff believe opening S-12 A and B early will also flood active alligator nests. While alligators are not endangered, they are important to the ecosystem.

“To summarize our assessment of the current situation, the service believes sparrows are actively nesting in subpopulation A and opening the S-12 A and B structures will flood sparrow nests. It would also negatively impact the plant community which serves as sparrow habitat. Therefore, the service recommends the capacity of the L-29 be used to its maximum as that will have no impact on sparrows and is the proper route for water in a restored system. If the corps seeks a deviation, because the service has allowed those before, we could potentially authorize another.

“If the stage in WCA-3A approaches 11.00, we will work with the corps and the district to identify actions, like opening S-343, S-344, and possibly S-12 A and B, to relieve the high water while trying to minimize impacts to sparrows. We believe opening S-12 A would be most impactful to sparrows because it delivers water directly onto the higher elevation ground where sparrows nest.”