• SBC Web Editor

Low water levels at Bombay Hook NWR

The following article was recently posted on the Bombay Hook NWR FaceBook page.


"There has been a lot of buzz lately about the low water levels at Bombay Hook NWR. While it doesn’t look great, it really isn’t such a bad thing.

The freshwater ponds are managed primarily for waterfowl and shorebirds. The water levels are dependent on rain fall. We let the water out in the spring but have no artificial way of putting more in. We haven’t manipulated the water since May. It’s currently 18 inches below the water control structure. This is due to evaporation and lack of rain.We can’t just let water in through the water control structures. The water in the bay is saline and the impoundments are freshwater. The salt would have a damaging effect on the ecology of the ponds. The soil/sediments, the invertebrates, plants, fish, reptiles and amphibians would all be negatively affected, and the pond would take several years to recover. The birds are not “confined” to a small space. They are choosing to be there because the fishing is easy and food is abundant. Herons and egrets successfully forage in the salt marsh every day. They are in the low fresh water impoundments currently because it is an all you can eat buffet. This low water creates a terrific wildlife viewing opportunity. The fish kills aren’t really a bad thing nor are they entirely a good thing. When they happen we monitor the water quality regularly. In a real pinch we could let bay water in and right back out to flush out the carcasses. One, maybe two tide cycles. This quick rinse doesn’t seem to have lasting effects. This is only practical in Raymond pool and Bear Swamp. Shearness is too big and deep to do this effectively. The down side to that approach is it completely empties the pool such as we see at Bear Swamp now. We don’t really want carp in the ponds. They get in during the spring when water levels are high. During the spring run off, the Delaware bay water is more fresh than salt. The carp are able to spread down stream in the Delaware river and up into tributaries. They follow water flow in search of suitable locations to spawn. The water control structures on the refuge keep saltwater out but, unlike water, carp can swim upstream and squeeze in past the flap gates. Carp are prolific and have a negative effect on water clarity and chemistry. They also eat many of the foods intended for wintering waterfowl. The fish kill prevents the population and the individual fish from getting too large. Hopefully that answers a lot of the questions and assuages some of the concerns. Thank you for continuing to visit and enjoy the wonderful wildlife that call Bombay Hook home.

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