Impacts
The changes to the hydrology of the Great Dismal Swamp has led to a series of impacts that the wetland is currently experiencing today.
- Fire has always been a use of practice to shape forest communities in the Great Dismal Swamp. However from the 1900 to 1945, the production of railroad and timbering activities started the increased frequency of fires that would burn for long period of time (FWS, 2006). "The Great Conflagration" is evidence of how alternations can cause drastic damage because, this fire event burned for 3 years from 1923-1926 and smoke filled the air around Norfolk and Hampton areas. Many other fire events have occurred including the 2 recent fires in 2008 and 2011. Lightning is the source of fire in the Great Dismal Swamp today and usually causes surface and ground fires at least twice a year (FWS, 2006).
- Human health is a major threat to these wildfires because it affects the air quality in the nearby urban communities. The impacts cause reduced visibility and high levels of ozone and particulate matter, the primary pollutant.These health issues affect the elderly as well as children. The symptom are even worse if they have asthma (FWS, 2006).
- Habitat fragmentation is another within the Great Dismal Swamp is the effects of . The Swamp has been shrinking since the 18th century because the land was drained for cultivation purposes. Over the years the Great Dismal Swamp has been sectioned into industrial parks, cities, and subdivisions (Rose, 1992) . Even though at least 47,000 ha were donated to the National Wildlife Refuge, there is still evidence of habitat loss by way of biological succession. Lake Drummond's water table has been lowered due to the removal of water, which means that drying is indeed occurring (Rose, 1992). This poses a threat to the animal species because many of them depend on specific forest communities to thrive.
- Water quality is also an issue in the swamp. The use of fertilizers and pesticides on crops such as soybeans, cotton, peanuts, and corn contaminant the water. Also the runoff from hog farming leads to surface water water pollution. This impacts the sediment flow into the refuge from uphill agricultural and timber lands; ultimately reducing the water quality and contaminating the shallow aquifer (FWS, 2006). It is believed that if this continues Lake Drummond will become impounded with sediment and the lake will no longer exist.