A pertinent question for water management in the Dismal 

 would be the degree to which modern ditches simulate natural 

 drainage. It is unknown to what extent the original dendritic 

 stream pattern penetrated the interior of the white cedar bog 

 which comprised the largest community in the swamp. Similar areas 

 for comparison, which have been undisturbed by artificial 

 drainage, are virtually nonexistent. 



Even if a complete drainage network existed, its tributaries 

 would have shallowed progressively toward the interior. This is in 

 striking contrast with the grid of 20th century ditches and canals 

 up to 10 ft deep, which dissect the heart of the swamp. The net 

 hydrologic effect must be a much more rapid removal of water 

 after rainfall than in the undisturbed swamp. 



The consequence of this effect for vegetation would be a 

 decrease in the time during which the water content of peat soils 

 exceeds saturation, and an increase in the length of time that 

 soils are aerated. In white cedar areas the equilibrium between 

 peat formation and decomposition clearly has been shifted toward 

 the latter process, with much of the upper surface exposed to 

 drying and subaerial oxidation. 



It appears that the center of the swamp has been most 

 affected, with white cedar undergoing rapid replacement by more 

 mesophytic community types. However, the periphery of the swamp 

 is also undergoing type conversion in many areas. Huge stumps 

 along the toe of the Suffolk Scarp demonstrate the presence of a 

 community type in which baldcypress was a canopy or emergent 

 species. The zone is now dominated by the slightly more mesophytic 

 black gum ( Nyssa sylvatica biflora ) and red maple, suggesting that 

 the slow feed of moisture from the swamp interior and from 

 uplands to the west originally maintained a higher water table 

 and/or longer hydroperiod than at present. 



To what extent roads in the Dismal Swamp act as dams is 

 unknown. Since the sands which were dredged from beneath the peat 

 horizon as roadfill are probably more permeable than the original 

 peat, it seems likely that the effect of their presence is 

 negligible in comparison with effects of the adjacent ditches. 

 The roads may not act as moisture barriers at all, unless in 

 areas where clay fill was trucked in. Resolution of this question 

 would necessitate understanding the composition of the road fill 

 along the different sections, and the original variation in rate 

 of water movement through peat at different depths. 



Restoration of original hydrology might seem a quixotic 

 endeavor in view of the extent to which it has been disturbed. 

 South of US 158, drainage and partitioning of the swamp into 

 small blocks for tree farming, agriculture and eventually peat 



71 



