Background Report

Environmental Constraints
Map 3: Environmental Constraints

Topography
Steep slopes are a development concern in the North City Sector. Steep slopes (greater than 25 percent) cover 12.8 percent of the sector and moderate slopes (16-25 percent) cover 16.8 percent of the sector. Environmental problems such as increased runoff, soil erosion, and loss of water quality and habitat often result from grading on and deforestation of moderate to steep slopes. This sector is located in between two steep ridges. On the northern edge is the Black Oak Ridge and on the southern edge is Sharps Ridge. The rest of the area is relatively flat, consisting of rolling terrain that is under 15 percent slope.

Steep slopes have limited protection.

Hydrology
Three creeks wind their way through the sector. First Creek flows south through the heart of Fountain City, but large portions of the creek run through concrete drainage ditches. Whites Creek, a tributary of First Creek, runs parallel to the east/west railroad line and intersects with First Creek near the North Broadway/I-640 interchange. These two creeks make up the majority of the area’s watersheds except for the northwestern portion of the sector, which drains into Knob Fork Creek.

First Creek channelized near commecial development.

According to the assessment by the Tennessee Department of Environment and Conservation (TDEC), these creeks are classified as “not supporting.” Not supporting means that water quality criteria created by the EPA are not being met and wildlife is seriously impacted. The primary sources of the low rankings are pollutants in urban runoff, severe alterations of natural stream banks, the aging sanitary sewer system and high-density urbanization. As of 1984, First Creek has had a water contact advisory posted due to bacteria within the water. First Creek’s problems include pathogens, nitrates, siltation, and habitat alterations. Whites Creek was listed only for pathogens and habitat alterations.

There are many areas in the sector that are prone to flooding. The area surrounding Whites Creek, which runs along McCampbell Drive, has an extensive floodplain especially between Beverly and Murphy Road. This limits the amount of development that can take place in this area. The floodplain of First Creek runs along North Broadway from Cedar Lane to Interstate 640. Future development in this area should be built with attention to water drainage problems. Significant flooding also takes place south of Dante Road due to the portion of Knob Fork that enters the sector for a short distance.

Additionally, sinkholes are present within this sector and create conditions that are unsuitable for development. A large sinkhole, which acts as a drainage basin, is located in the Harrell Hills subdivision between Clairidge Road and Gaines Road. The area was flooded so often that the city bought the surrounding lots and removed the existing structures. The area is now designated as a critical watershed in the City’s Stormwater Ordinance and requires stormwater retention for development. Impervious surfaces in the neighborhood, such as asphalt roads, roofs, and driveways, increase the amount of rainwater that flows into this sink hole. This problem could increase in the future if the amount of impervious surfaces from development continues to grow.