Why No Comprehensive Steep-Slope Regulations For Chattanooga?

  • Wednesday, August 24, 2016

In real estate development, there are things called BMPs (Best Management Practices). BMPs are standards intended to minimize, and control the various risks associated with and created by the development of property. They act like, and perform the same function as speed limits.  

For example, as the various risk conditions increase on roads, one way to minimize and control those risks is by lowering the speed limit. As one moves from driving on the interstate, to driving on a state highway, to driving in a residential neighborhood, to driving in a school zone with the yellow lights flashing and children present -- the various risks increase, and the speed limit is lowered.  

Real estate BMPs operate In a similar way. When developing real estate, as the property's slope grade increases, so do the various risks (e.g., safety, environmental, etc.). One way BMPs work to minimize those risks is by lowering the density (e.g., housing units per acre) as the slope grades increase. 

For example, in an area where zoning allows residential development at, say, eight units per acre - as the slope grades increase, the slope BMPs would lower the upa.  

These BMPs usually take effect when slope grades approach 15 percent. For example, the Chattanooga BMPs are contained in the two page Steep Slope Management report. Many areas have similar BMPs, although most are much more comprehensive than Chattanooga's, e.g., Knoxville's "Hillside and Ridgetop Area Protection Plan".  

The SSM can be found here

The Chattanooga BMPs state that, when slope grades are between 16-25 percent, the maximum density should be limited to 1-3 upa - and when grades increase above 25 percent, the risks become so great that the maximum density should drop to 0.5 upa.  

And the Chattanooga BMPs have a limit -- when the cut and fill techniques required to develop steep slopes begin to create fill slopes exceeding 33 percent, the safety and environmental risks become so great, these BMPs recommend that no development be allowed in these areas. To put this in perspective, the "Hamilton County Tennessee Natural Hazards Mitigation Plan" defines slopes with grades of 35 percent and greater as "potentially vulnerable to landslides", p 64.  

The problem with the Chattanooga BMPs, is that they only have the authority government officials chose to give them. When these officials chose to ignore them, the safety and environmental protections they were intended to provide are compromised. 

A good example is the recent approval by both the Regional Planning Commission (June, 13) and the Chattanooga City Council (Aug. 16) of the following development:  

Case# 2016-089 - which can be found here.

While it was approved for nearly eight upa or 246 units total, looking at this 32+ acres site on the GIS topo map reveals it to be a very steep 230 foot hill - e.g., four of its multi-story buildings will be located in an area 150 feet above its base on slope grades exceeding 50 percent. 

This property is at the intersection of I-24 and Cummings Highway, in the northeast quadrant - it has a water tank and TVA power line running across it.  

According to both the Chattanooga and Knoxville BMP's, about half of this property should be limited to 1-3 upa (about 16-48 units total) and the other, even steeper half, to 0.5 upa (about eight units total). In addition, those four buildings are in an area the BMPs recommend be left undisturbed. 

This would be similar to giving someone permission to drive through a school zone, with yellow lights flashing and children present, at 50 mph. 

Given the high percentage of steep sloped property in this area, the environmental and safety issues created by its development, the fact that many other areas have them, and for years our comprehensive plans and other documents have called for one (e.g. Chattanooga CompPlan 2030, pp 106-109, 112) -- Why is it that Chattanooga does not yet have a comprehensive and objective steep slope policy? 

John Sullivan


Opinion
Democratic View On Top State Senate Issues - March 18, 2024
  • 3/18/2024

Campbell bill seeks to save lives by studying suicide trends in Tennessee 3 p.m. Senate Regular Calendar — SB 1787 , by Sen. Heidi Campbell, would require state health officials to produce ... more

The Odor Of Mendacity - And Response (2)
  • 3/16/2024

The Fulton County judge, Scott McAfee, overseeing the Fani Willis prosecution of Donald Trump and eighteen other defendants has spoken. In response to a motion by defendants to remove Willis ... more

Capitol Report From State Rep. Greg Vital For March 15
  • 3/15/2024

General Assembly confirms new Tennessee State Supreme Justice Members of the General Assembly confirmed the appointment of Mary L. Wagner to the Tennessee Supreme Court in a joint session ... more