AGENDA #5d

 

MEMORANDUM

 

TO:                  Mayor and Town Council

 

FROM:            W. Calvin Horton, Town Manager

 

SUBJECT:       Preliminary Report on Lake Ellen Watershed Field Review

 

DATE:             August 27, 2001

 

 

The purpose of this report is to provide the Council with information about the existing condition of sediment and erosion control measures within the watershed above Lake Ellen, including recommendations for improvements.

 

A follow-up report has been scheduled for the regular business meeting on September 24^th, 2001, which will include a presentation by Dr. Larry Band, Voit Gilmore Professor of Geography, UNC-Chapel Hill.  Dr. Band, who is familiar with Lake Ellen and its watershed, will discuss watershed dynamics including the natural and man-made forces causing turbidity in lakes and deposition/scour in streams. 

 

BACKGROUND

 

On July 2^nd the Town Council received a petition from the Lake Ellen Homeowner’s Association (see Attachment 1) asking the Town to address certain issues relating to turbidity problems in Lake Ellen. The petition specifically asked that the Town consider the following: (1) alternative technologies for controlling stormwater sediment and turbidity, (2) requiring stormwater management on all land disturbed areas greater 8,000 square feet at any one time, (3) implementing measures to require erosion prone and/or disturbed areas to be covered at the end of each work day with “blankets” and,  (4) direct Town and County staff to visit construction sites within the watershed to investigate where problems may exist and to identify potential improvement opportunities with respect to soil erosion.

 

The Town Council received this petition and referred it to the Manager, directing the Manager to have Town and County staff inspect the watershed to determine if development is complying with the soil erosion and sedimentation regulations and to correct any activity that is not in compliance. We responded that the Town inspectors routinely work with County erosion control staff during field inspections, and that consideration of ordinance related items could not occur in the short-term because of the intergovernmental nature of the process.

 

The Council requested that the Town’s Stormwater Management Engineer analyze the material causing the turbidity in Lake Ellen, and attempt to address the sources of the material. This issue will be addressed in our follow-up report in September.

 

DISCUSSION

 

The Town Engineering staff and the Orange County Sediment and Erosion Control Officer inspected the following development sites within the Lake Ellen Watershed:

 

• Parkside; a single family development
• The Estates; a single and multi-family development
• Northwood; a single family development
• Windsor Park; a single family development

 

Of these four projects Parkside and Northwood have the most active construction underway.  Windsor Park and The Estates are near completion and have minimal construction activity underway which could result in excessive erosion/sedimentation.  We did not note any physical problems or non-compliance issues with Windsor Park or The Estates development projects. 

 

Our field inspection did reveal items associated with the Parkside and Northwood projects that needed corrective actions, as follows:

 

• In one of the early phases of Northwood, an established ditch behind two houses was found to be eroding along its bottom.  The Orange County Soil Erosion and  Sedimentation Control Officer has contacted the developer to have the ditch stabilized.
• In a recent phase of Northwood, we noted a sewer installation that resulted in some land disturbance next to a stream.   This area should be stabilized with ground cover vegetation.  The Orange County Soil Erosion and Sedimentation Control Officer has notified the responsible parties to have this area properly stabilized.
• In Parkside, an area exists along a stream where the existing silt fence was full and was being overtopped.  The Orange County Soil Erosion and Sediment Control Officer has notified the responsible parties to correct this problem.

 

We will comment on the status of these issues in our follow-up report to the Council in September.

 

While our inspection found some problems, we noted that, for the most part, development activity in the Lake Ellen watershed is complying with applicable soil erosion and sedimentation regulations.  In some cases, developers and contractors are going beyond the minimum requirements, such as surrounding single-family lots with silt fence.

 

We are making arrangements to inspect these and other sites in the Lake Ellen watershed with representatives of the Lake Ellen Homeowners Association. We want to get their input about areas that they feel may be contributing to the turbidity of Lake Ellen, and discuss with them any other concerns. During this field inspection, we will again inspect the areas described above to ensure that the necessary corrections have been made and to identify any new problems needing immediate attention.

 

We will also continue to discuss this matter with the development representatives, who have indicated willingness to cooperate in any areas deemed appropriate by County and Town staff subject to reasonable limits on what they would agree to.

 

ATTACHMENTS

 

1.  June 25, 2001 Lake Ellen Homeowners’ Petition (p. 3).