104 
William F. Adams 
for identification of species. Gender problems in the species names used 
by previous authors have not been rectified. 
HISTORY OF GREENFIELD LAKE 
Greenfield Lake was created prior to 1750 by the impoundment of 
a small low-lying stream located south of Wilmington to provide a 
source of fresh water for a nearby rice plantation and for the operation 
of grist and saw mills. The rice plantation, lake, and surrounding lands 
were known collectively as “Greenfields” (Moore 1968). The surface 
elevation is 1.85 m above mean sea level, the surface area is 75 ha, and 
the drainage basin is approximately 1,100 ha. Maximum depth is 
approximately 2.5 m. 
The City of Wilmington purchased the lake in 1925 for use as a 
public park, and a circumferential road approximately 8 km long was 
constructed as a public works project during the Great Depression 
(Moore 1968). In 1935, fallen trees were removed from the lake and the 
surrounding area was landscaped (Moore 1975). Removal of marsh 
grasses and additional snags took place in 1945 for mosquito control 
(Appleberry 1945). 
Today, Greenfield Lake is well within Wilmington, and its watershed 
is almost completely developed. Land use consists primarily of residential 
and commercial areas with open space in the form of a golf course and 
small, isolated tracts of woodlands. Lands immediately adjacent to the 
lake are still used as a public park, which is a major recreation center 
for Wilmington. 
Urbanization of the watershed has resulted in a decreased detention 
time for storm waters and, consequently, an increased introduction of 
nutrients, pesticides, and metals into Greefield Lake. Breaks in sewer 
lines on the bottom of the lake and sewage overflow from nearby 
manholes during storms have also added large pulses of nutrients. The 
latter are now a major problem and in recent years have contributed to 
severe algal blooms ( Lyngbya ). Control has been attempted through 
algacides (chelated copper and dichlobenil); introductions of the exotic 
fishes tilapia, Tilapia aurea (Steindachner), and grass carp, Ctenopharyngo- 
don idella Valenciennes; and partial drawdowns during the winter 
months to desiccate and freeze the algae. Central portions of the lake 
have been dredged in attempts to remove nutrient-laden sediments and 
deepen the lake beyond the photic zone. 
All of the tributaries leading into Greenfield Lake have been 
channelized to improve drainage in the basin. Maintenance of the 
channels is periodic and is confined to portions upstream of Lakeshore 
Drive, the perimeter road. The outlet creek below the dam has been 
