Triadelphia Reservoir and Rocky Gorge Reservoir are owned and operated by the Washington Suburban
Sanitary Commission (WSSC). Triadelphia is oriented slightly northwest to southeast along the Patuxent River which serves as the boundary between Howard County to the east and Montgomery County to the west. The two reservoirs are surrounded by 6,000+ mostly wooded acres.
Triadelphia is the larger of the two reservoirs and attracts a wide variety of birds not consistently seen elsewhere in the county. Access to this reservoir, although limited, is much better for birders than that at Rocky Gorge.
Although boating and fishing are allowed, shore access is minimal. Birders may view portions of this reservoir at three public sites in Howard County: Brighton Dam, Big Branch, and Pigtail. There are separate site guides for each. In addition, from Montgomery County, views from the parking area at Greenbridge Road and the trail down to the reservoir at Triadelphia Lake Road allow birders to look across the water into Howard County territory. Below are directions for Greenbridge Road and Triadelphia Lake Road. Consult A Birder’s Guide to Montgomery County, Maryland (2nd. ed.) for complete information on these two.
Notable birds: Cackling Goose, Eurasean Wigeon, Surf Scoter, White-winged Scoter, Black Scoter, Long-tailed Duck, Wild Turkey, Northern Bobwhite, Red-throated Loon, Red-necked Grebe, Western Grebe, Least Bittern, Snowy Egret, Little Blue Heron, Tri-colored Heron, Cattle Egret, Glossy Ibis, Bald Eable, Rough-legged Hawk, Golden Eagle, Peregrine Falcon, Sandhill Crane, Black-bellied Plover, American Golden-Plover, American Avocet, Ruddy Turnstone, Red Knot, Sanderling, Western Sandpiper, White-rumpted Sandpiper, Baird’s Sandpiper, Dunlin, Stilt Sandpiper, Short-billed Dowitcher, Long-billed Dowitcher, Wilson’s Phalarope, Sabine’s Gull, Iceland
Gull, Lesser Black-backed Gull, Glaucous Gull, Black Tern, Common Tern, Forster’s Tern, Olive-sided Flycatcher, Alder Flycatcher, Philadelphia Vireo, Common Raven, Marsh Wren, Gray-cheeked Thrush, Snow Bunting, Golden-winged Warbler, Prothonotary Warbler, Connecticutt Warbler.
Reservoirs are open from March 15 to November 30. Day use or seasonal permits are required for boating, fishing (along with state fishing licenses), and birding. Rangers are security personnel. They enforce regulations and issue citations for trespassing as well as for fishing and boating violations.
Bird and dragonfly species lists for all Triadelphia and Rocky Gorge reservoir Howard County sites have been combined.
Each reservoir site has a photo page. In addition, there is a page titled Triadelphia Bird Photos.
WSSC has granted access to additional adjacent land not available to the general public. See Additional Land Open for MOS Members. Hunting is allowed in defined areas; a free map is available at the Brighton Dam office. Dates are posted at each public access site at the beginning of the hunting season. The entire reservoir is closed on hunting dates.
For additional reservoir information, visit the WSSC website at www.wsscwater.com and click on Public Information or call the Brighton Dam Information Center 301-206-7485.
Compiler: Joanne Solem
Directions to Greenbridge Road Recreation Area
For details, see Greenbridge Road, Sunshine in A Birder’s Guide to Montgomery County, Maryland (2008 rev).
Directions are included here because it is also a great location to see birds behind Brighton Dam that are in Howard County.
To reach the intersection of Brighton Dam Road and Highland Road there are two options. From US 29 go west on MD 216/Highland Road 6.0 miles to a left turn on Brighton Dam Road OR take MD 32 to Clarksville, go west on Ten Oaks Road 0.6 mile to the junction with Brighton Dam Road (as Ten Oaks Road makes a wide right-hand curve, Brighton Dam
Road goes straight); continue 1.5 miles to the intersection with Highland Road. Continue straight on Brighton Dam Road 1.7 miles to the dam (the road runs along the top of it). Cross the dam and continue to the intersection with New Hampshire Avenue (MD650) and turn right. Continue to Greenbridge Road and turn right. There is a metal gate after 0.5 mile. (The gate is closed during the no-fishing season and between dusk and dawn at all times.) Continue 0.1 mile to the parking lot. There is a trail (dotted line) from the parking lot.
Directions to Triadelphia Lake Road
For details, see Triadelphia Lake Road, Sunshine in A Birder’s Guide to Montgomery County, Maryland (2008 rev).
Directions are included here because it is also a great location to see birds at the upper end of Triadelphia Reservoir that are in Howard County.
Take MD 97 (Roxbury Mills Road) south into Montgomery County. Turn left onto Triadelphia Lake Road and drive to the parking lot at the end. You will see a fishing deck dedicated to wounded veterans. (All of this area is Montgomery County.) Take the steps on the north side of the parking lot and follow the path for 10-15 minutes keeping the water on your right side. You will get to an area where the path and the river makes a 90 degree turn to the left. Just after this you will see two large logs on your right and then a small path on your right. Take this path down to the edge of the mud flats. The Patuxent River will be on your right and also straight ahead because it makes a 90 degree turn to the left. The right side of the river is Howard County and the left side is Montgomery County. Most of the mud flats in front of you is in Montgomery County. In front of you is a small grassy knoll and beyond it some large rocks. The grassy knoll is
Montgomery County and the large rocks with its mud spit is Howard County. The area with the large trees in front of you is Howard County. What looks like the main river going north (where the river turns to the left) is actually Cattail Creek and is all Howard County.