AGENDA #5d
MEMORANDUM
TO: Mayor and Town Council
FROM: W. Calvin Horton, Town Manager
SUBJECT: Response to Petition from Cedar Fork Creek Property Owners Requesting Town Assistance with Erosion and Flooding Problems
DATE: May 13, 2002
The following report is in response to a petition from Cedar Fork Creek neighbors seeking assistance from the Town for relief from flooding and erosion problems associated with Cedar Fork Creek above Eastwood Lake. Attachment #1 is a copy of the petition.
BACKGROUND
On January 14, 2002, the Council received a petition from citizens who live near Cedar Fork Creek asking that the Town provide appropriate planning, engineering and remediation assistance to stabilize the creek bed, reduce erosion and mitigate the threat of flooding to nearby homes.
The portion of Cedar Fork Creek that is the subject of this petition extends from immediately upstream of Brookview Drive to Eastwood Lake. With the exception of the segments that flows under Brookview Drive and North Lakeshore Drive, Cedar Fork Creek is entirely on private property with portions of the stream banks within an Orange Water and Sewer Authority (OWASA) easement for a sewer line that runs from North Lakeshore Drive along the northeast side of the creek. Please the see the map Attachment #2.
Over the past several years, Town staff has provided technical assistance to OWASA and to several of the petitioners regarding stream bank stabilization methods and has provided advice about possible funding sources for stabilization projects to mitigate erosion and flooding problems that have been identified in this area.
In April 2002, Town staff met with several of the petitioners and OWASA staff to hear their concerns and to discuss possible solutions. The meeting resulted in a mutual understanding of how the petitioners might accomplish a satisfactory outcome and how the Town and OWASA could provide assistance in achieving that outcome.
DISCUSSION
Cedar Fork Creek, like most natural streams, shifts its alignment as a result of several factors including changes in its watershed characteristics, soil-type and vegetation cover, stream gradient, and development along its banks and within its floodplain. This instability is typically exhibited as stream bank erosion, down-cutting (lowering of the creek bed), deposition of sediment, meandering, and widening.
Due to the relatively flat ground adjacent to this segment of Cedar Fork Creek, the stream periodically overtops its channel and inundates its natural floodplain during and after certain storm events. This is a typical occurrence for unregulated streams; however, it results in flooding problems for property owners within the floodplain adjacent to this section of Cedar Fork Creek.
The nature and characteristics of the watershed upstream from this portion of Cedar Fork Creek have changed significantly over time, from forested to agricultural to moderately urbanized. These changes have resulted in changing stormwater runoff characteristics. In recent years, a series of significant and sometimes extraordinary weather events, such as the severe rainstorm of July 2000, have amplified changing conditions on Cedar Fork Creek. The watershed evolution and periodic storms have exacerbated problems associated with stream flow dynamics, erosion and sedimentation, and over-bank flooding. We would expect the changing conditions in and along Cedar Fork Creek to continue as the natural stream environment reacts to rainfall and runoff events.
Town staff members have on several occasions responded to inquiries and discussed creek-related issues and problems with some of the property owners in this area. Following receipt of the petition, Town and OWASA staff again met with several property owners on April 10, 2002 to review the petitioners’ concerns and to clarify our understanding of the issues. At that meeting, Town staff also explained existing Town policy and practice regarding improvements to natural streams on private property.
The petition identifies four issues of concern, and requests that the Town provide appropriate planning, engineering and remediation assistance to stabilize the creek bed, reduce erosion, and mitigate the threat of flooding. The following lists the petition concerns and provides associated staff comments:
1) Petition Statement: The homeowners along Cedar Fork Creek are suffering increasing problems with erosion and flooding.
Staff Comment: We agree that this section of Cedar Fork Creek is experiencing stream bank erosion, in addition to sedimentation, widening and down-cutting. We also agree that the stream periodically overtops its banks and spreads onto its natural floodplain, causing flooding problems on properties in the floodplain. These conditions, to varying degrees, are occurring on and along all of the natural streams in Chapel Hill. Please refer to attached photographs #1, #2, #3, #4, and #5.
Approximately three years ago, Town staff arranged a meeting between several of the petitioners and representatives of the North Carolina Sea Grant Program to discuss a potential grant for stream stabilization project along this stretch of Cedar Fork Creek. The Sea Grant Program performed a feasibility analysis, and determined that the project would cost more than the funding that was available through its program resources. The Sea Grant program notified the interested property owners that it could not undertake the project, and suggested that the neighbors apply for a Clean Water Management Trust Fund grant or a United States Environmental Protection Agency (USEPA) 319 grant to undertake a stream stabilization project.
The Clean Water Management Trust Fund and USEPA 319 grants are State administered matching grant sources made available to public and private sectors to restore, maintain and/or enhance riparian areas for water quality and habitat improvement purposes. Grant applications are only accepted from owners (or stakeholders) of benefited properties. In this case, only private property would be benefited and therefore the grant applications would need to be submitted by the private property owners, not by the Town.
There may be an opportunity to provide Town assistance through the North Carolina Wetlands Restoration Program (NCWRP). The Town has recently signed a Memorandum of Understanding with the NCWRP with the goal of identifying projects in the watershed to improve water quality. This section of stream is within the study area.
We think that these grant programs could offer the Cedar Fork Creek property owners an opportunity to secure matching or total funds to undertake a project to stabilize the stream banks on their properties. Town staff has and will continue to provide advice and assistance to owners interested in pursuing grant funds for a stream stabilization project in this area.
Town staff also suggested that some of the petitioners could mitigate the effects of periodic flooding on their property by implementing flood-proofing measures. The North Carolina Division of Emergency Management maintains a web site that contains information on techniques to retrofit at-risk structures with flood proofing measures. We suggest that interested citizens visit the web site at www.ncem.org/mitigation/index.htm to review their options. Additionally, owners may elect to hire a qualified Engineer or Architect to make flood-proofing recommendations and Town staff also can provide technical advice in that regard.
2) Petition Statement: The Town of Chapel Hill is responsible for effective management of storm water runoff within Town boundaries.
Staff Comment: The Town provides some regulation of stormwater runoff and development utilizing Council adopted zoning regulations, design standards, and Development Ordinance provisions including the Resource Conservation District (RCD) requirements. The RCD requirements establish buffers along streams and preclude structures from being built where they are at a risk of being flooded. The buffer widths are intended to allow an area for streams to naturally meander and to periodically flood, while keeping development far enough away or elevated so that it is not adversely impacted.
The RCD Ordinance was adopted in 1984, after most of the homes in the petition area were constructed. If these homes were built under the current RCD requirements,, many of them would not be permitted to be constructed in their present location and/or at their present finish-floor elevation.
Post-construction stormwater runoff has been regulated by the Town’s design standards for a number of years. With evolving technology and understanding of stormwater management science, engineering, and watershed dynamics, the Town’s stormwater management standards and practices are revised from time to time to provide the most effective measures possible. For example, the proposed revisions to the Town Development Ordinance include a variety of changes intended to implement more stringent stormwater management standards and requirements for all types of development in Chapel Hill.
We believe that the Town has been reasonable and prudent in exercising the authority it has over storm water runoff within the Town boundaries, and the Town will continue to improve its stormwater management oversight, programs, policies and regulations to the extent practicable. This includes the consideration of a stormwater utility designed to provide sufficient funds to carry out a comprehensive stormwater management program. Such a program could include water quality activities such as stream restoration projects throughout Town to address issues such as this petition.
3) Petition Statement: The Town of Chapel Hill has approved OWASA construction projects in and around the Cedar Fork Creek bed.
Staff Comment: Orange Water and Sewer Authority (OWASA) upgraded the existing sanitary sewer line along this section of Cedar Fork Creek approximately three years ago. The upgrade was undertaken to mitigate increasingly frequent sewer overflows into the creek due to insufficient capacity in the existing lines. The Town reviews and comments on OWASA plans where the public right-of-way or the Resource Conservation District are involved.
Town and OWASA staff met at the site to discuss this petition and the concerns the citizens expressed about the OWASA sewer project. OWASA representatives also attended the above-referenced April 10 meeting with residents and Town staff. Most of the OWASA easement, including the stream bank areas, appears to be in satisfactory condition. We did note locations where the creek was showing natural erosion and sedimentation characteristics. Stream areas disturbed by the sewer installation were stabilized by the OWASA contractor as part of the construction contract using standard procedures, such as placement of rock lining on embankments and reestablishment of vegetative cover material. Please refer to Attachment #5, Photos #1 - #5.
OWASA staff routinely monitor sewer installations in or near streams to identify and mitigate erosion or sedimentation problems affecting the stream and/or the sewer line. OWASA inspectors have been and will continue to inspect this area of Cedar Fork Creek for problems. Attachment #3 is a copy of a letter from OWASA in response to our February 19, 2002 field meeting at the site. Attachment #4 is a copy of email correspondence from OWASA following the April 10, 2002 meeting with residents.
4) Petition Statement: Construction has seriously destabilized the banks of Cedar Fork Creek, resulting in dramatic widening of the creek and increased flood risks to nearby homes.
Staff Comment: At the April 10, 2002 meeting, residents clarified that this statement referred to general construction throughout the stream watershed, not specifically to the OWASA sewer line construction adjacent to their properties.
We observed that the stream is experiencing erosion, deposition and meandering characteristics that are typical in and around natural streams Town-wide and affect all adjacent properties in one way or another. Long-term residents of properties in this area advise us that their concern is not that normal erosion, sedimentation, and meandering is occurring; but that the rate of change is increasing as is the extent of impacts on their property.
As noted previously, OWASA has agreed to continue to monitor conditions in this area, and to stabilize eroding stream bank areas affecting or affected by the sewer installation project. Town staff has assisted property owners with identifying grant assistance to stabilize this segment of Cedar Fork Creek.
CONCLUSION
We understand the concerns expressed in this petition. However, all streamside properties are subject to the negative effects of erosion, sedimentation, and flooding. We think that mitigation of the negative effects are primarily the responsibility of the property owners who also benefit from the positive effects of having a stream on or near their property. Town staff has and will continue to provide technical assistance for funding a mitigation project on this section of stream.
We have recommended that interested property owners apply to secure matching funds through the State or other available sources for a stream restoration project grant. We think that the Clean Water Management Trust Fund, the USEPA 319 Grant program and the NCWRP would be the best opportunities to pursue. We have provided the property owners with contact information for each of these potential grant sources and we will discuss this site with the NCWRP in the watershed planning effort as projects to improve water quality in the watershed are identified.
Flood-proofing measures can also be explored and implemented by the owners to provide increased protection from flooding. Experienced consulting engineering or architectural firms can provide recommendations that are specific to each owner’s needs. Town staff will be available to provide technical advice and information upon request, and the North Carolina Emergency Management Agency has a web site (www.ncem.org/mitigation/index.htm) which can provide further information.
ATTACHMENTS
1. Petition from the Cedar Fork Creek property owners (p. 6).
2. Vicinity Map (p. 7).
3. OWASA February 20,2002 letter (p. 8).
4. OWASA April 19, 2002 email (p. 10).
5. Photos #1,#2,#3,#4, #5 (p. 12).