A Hard Rain’s A-Gonna Fall

by Ron Klauda

(26 March 2024)

This song by Bob Dylan is an apt description of what the Hellen Creek watershed experienced on March 23 rd . Mike Gardner, President of the Cove Point Nature Heritage Trust, recorded 4.33 inches of rainfall over about 9-1/2 hours at his Tempest One weather station at Preston Point, Lusby MD. Gravity took control of this downpour that fell onto steep slopes of already saturated and highly erodible Calvert County soils. Then, upper Hellen Creek turned into a raging, chocolate brown torrent (see videos).

Non-tidal streams are dynamic systems, so seasonal and storm-associated changes in flow are to be expected. Naturally, along with elevated flows come increases in the downstream transport of sediments---soil erosion from upslope areas plus stream bank and bed erosion.

Human activities can exacerbate natural variations in stream flow and sediment transport. Stormwater runoff and soil erosion from upstream construction sites, urban areas, and places in the landscape where vegetation has been removed can have severe negative impacts on stream biota. High flows can destroy aquatic vegetation, degrade physical habitat, and expose benthic macroinvertebrates and fish to an influx of toxic contaminants washed off the human-altered landscape.

The Friends of Hellen Creek don’t know the severity of the ecological impacts of the caused by the March 23 rd “flood”. For sure, the videos clearly show that a lot of sediment was transported downstream to the tidal creek and on into the Patuxent River….not good news for the Chesapeake Bay’s sediment and nutrient diet. On a more positive note, the beaver ponds on upper Hellen Creek, just downstream from the Old Mill Rd. culvert where the videos were shot, likely intercepted some of the eroded sediments.

Climate scientists tell us that annual rainfall is increasing in Maryland, and more of our rain is now falling as downpours (like the March 23 rd storm), which is increasing the frequency of inland flooding events (like the videos in upper Hellen Creek show). This situation is only expected to worsen by 2050 and beyond. Better stormwater management is one important adaptive strategy that we must embrace to protect the Hellen Creek watershed, the Patuxent River, and the Chesapeake Bay.