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HomeMy WebLinkAbout19950786 Ver 1_WQ and Sewer Service Technical Memo_19950728~, , a~ BRUNSWICK COUNTY REPLACEMENT OF BRIDGE NO. 198 ON SR 1172 OVER ATLANTIC INTRACOASTAL WATERWAY AT SUNSET BEACH, NORTH CAROLINA FEDERAL AID PROJECT NO. BRS-1813(1) STATE PROJECT N0.8.2230101 TIP NO. B-682 WATER QUALITY AND SEWER SERVICE TECHNICAL MEMORANDUM Prepared For: OF S~OR7/~ ~ ~~ ~`i G7~ p o a 4 fi~ h~ ~~~ ~,~~ ~rfiNT OF ;R~`N~~o PLANNING & ENVIRONMENTAL BRANCH NORTH CAROLINA DEPARTMENT OF TRANSPORTATION II June 1995 q~~~c~ BRUNSWICK COUNTY REPLACEMENT OF BRIDGE NO. 198 ON SR 1172 OVER~ATLANTIC INTRACOASTAL WATERWAY AT SUNSET BEACH, NORTH CAROLINA FEDERAL AID PROJECT NO. BRS-1813(1) STATE PROJECT NO. 8.2230101 TIP NO. B-682 c ~ WATER QUALITY AND SEWER SERVICE TECHNICAL MEMORANDUM Prepared For: Planning and Environmental Branch North Carolina Department of Transportation Prepared By: Greiner, Inc. Raleigh, North Carolina June 7, 1995 Copyright ° 1995 Greiner, Inc. 1 1 1 1 1 1 TABLE OF CONTENTS Section Page I. Introduction ........................................... 1 II. Project Description ....................................... 1 III. Setting and Location ...................................... 2 IV. Issues and Associated Assumptions ............................. 2 V. Existing Utilities ........................................ 3 VI. Planned and Proposed Utilities ................................ 3 VII. General Discussion and Background Information ..................... 4 VIII. Stormwater Management .................................... 6 IX. Conclusion ............................................ 7 References ............................................ 9 Attachments Attachment A: Location Map Attachment B: Project Area ' I. INTRODUCTION ' The purpose of this Memorandum is to assess and document the existing and planned water and wastewater/sewer utilities for the Town of Sunset Beach and the surrounding area. Also, those issues affecting water quality will be discussed. This discussion will _ take place within the framework of the proposed Sunset Beach bridge replacement project. However, it is not within the scope of this Memorandum to fully address those related Natural Resource and Land Use issues and associated impacts, which will be examined in , greater detail and addressed in subsequent documents; including the Natural Systems Technical Memorandum and the Draft Environmental Impact Statement (DEIS). ' II. PROJECT DESCRIPTION ' The Sunset Beach Bridge Replacement project study area is located in the extreme " southeast portion of the state in Brunswick County (Attachment A). The general study area includes an area that extends from the island, across the Atlantic Intracoastal ' Waterway, to NC 179 on the mainland in the Town of Sunset Beach (Attachment B). The purpose of the proposed action is to replace a deficient and functionally obsolete ' bridge. This will improve highway access and safety between the island portion of the Town of Sunset Beach and the Brunswick County mainland and will enhance watercraft operation on the Intracoastal Waterway. The existing bridge is a single-lane, steel-barge, swing-span draw bridge, with wooden approach spans, and crosses the Atlantic Intracoastal Waterway at mile 337.9. The bridge was constructed around 1953 by a private developer of the Sunset Beach area. The beach road was added to the State System in 1960 as SR 1172, at which time the bridge underwent substantial reconstruction. The North Carolina Department of ' Transportation (NCDOT) has maintained the bridge since it re-opened in 1961 through a series of repairs and/or replacement of the structural wooden members. The bridge was last inspected on March 10, 1992. The present condition is rated as poor, with an ' estimated remaining life of two years. The sufficiency rating is 4.0 on a scale of 0 to 100, with 100 being perfect condition. It is designated as being both structurally deficient and ' functionally obsolete, and due to its poor condition, restrictive maximum load limits of 16 tons for single vehicles and 21 tons for truck and trailers have been imposed. The existing bridge provides one-lane traffic operation using traffic signals at each end of the bridge to control alternating directions of traffic flow. Between April 1 and October 31, draw openings for passage of pleasure watercraft are restricted to once an hour, on ' the hour, but is opened on demand for commercial vessels. During the shoulder months, November 1 through March 31, the bridge is opened on demand for all vessels. Both variable height bascule (draw bridge) and high-level, fixed-span designs are being considered during project development. Existing location (center corridor) and 1 1 1 1 relocation alternatives, both to the east and to the west, as well as a no-build alternatives are being developed. Tunnel and ferry schemes are also being considered during the initial corridor development phase of the study. Additionally, no-build alternatives, including continual normal maintenance and the complete rehabilitation of the existing structure will also be addressed during the DEIS phase of the project. III. SETTING AND LOCATION The Town of Sunset Beach, incorporated in 1963, is located in the extreme southeastern portion of the state. A portion of the town is an island separated, from the mainland by the Intracoastal Waterway. The island is approximately two miles long and one-half mile wide. Existing land use on the island consists almost exclusively of residential structures. Nearly all the developable land on the island has been subdivided into building lots. There are 1,497 platted lots, of which some 60 percent are already developed (Hayes and Associates, 1994a). Based on 1992 land use data (Hayes and Associates, 1993), there are 833 single family residences, 128 duplex units, 6 multifamily units, and 40 motel units. The Town is a resort community and experiences wide fluctuations in population according to the season, drawing most of its livelihood from tourism, primarily summer rentals, golfing, marine recreation and fishing activities. IV. ISSUES AND ASSOCIATED ASSUMPTIONS One of the issues to be addressed in the Draft Environmental Impact Statement concerns that of cumulative impacts driven by the increased growth and development that could result from the bridge replacement project. It has been postulated that the replacement of the existing bridge, thereby improving access, would foster and accelerate development, some of which may be out of character or undesired. This same line of reasoning has also been applied to the construction of a centralized wastewater treatment system. This argument has been carried even further in suggesting that the bridge replacement would also serve as an inducement to the construction of a wastewater treatment system. Two issues have been raised in this regard: (1) because it is theorized that the bridge will accelerate development, it is thought that the wastewater treatment system will logically, and necessarily, follow; (2) it is also theorized that the construction of ahigh-level, fixed span bridge would facilitate the implementation of the wastewater treatment system by allowing a line between the mainland and the island to be attached to the bridge. While these are reasonable assumptions, recent studies indicate that bridge replacement is a separate issue from the development of a centralized wastewater treatment system and associated impacts to water quality. These associated impacts include stormwater runoff. 2 V. EXISTING UTILITIES The water system currently supplying the Town of Sunset Beach and its extraterritorial area (ETA) is owned and operated by Brunswick County. The Town actually buys its treated water from the Brunswick County Water Service. The Town is responsible for distribution of the water throughout its jurisdiction. All town residents are required to be connected to the public water system and pay the minimum water usage fee. The majority of the ETA residents are also connected to the system. The Town serves approximately 1,300 customers within the corporate limits and 800 customers within the extraterritorial limits (Hayes and Associates, 1993). The 1992 Sunset Beach Land Use Plan states that the Brunswick County Water Service and the Town of Sunset Beach will have sufficient capacity to accommodate the projected peak population through 1997. It was estimated that the peak demand for Sunset Beach is only four percent of the County's total capacity. With respect to wastewater, the Town is served by ground absorption waste disposal systems (individual septic tanks) that are approved and permitted by the Brunswick County Health Department. This is a concern because of the lack of suitable soils for these types of systems. There have also been documented septic tank system failures and septic tank operational problems identified; both on the island and mainland areas within Calabash and Sea Trail Plantation. Additionally, there are a number of building sites, located both on the mainland and the island, for which the Brunswick County Health Department will not issue septic tank permits. Lot inspections for septic tank permit approvals are only conducted after an application for a building permit has been filed. Therefore, the number of undeveloped lots which can not be permitted for septic tanks can not be readily, quantified. It should be noted that sewage treatment package plants can be constructed in areas that are not suitable for septic systems. Package plants may not, however, be cost effective in all cases. With respect to stormwater, the Town of Sunset Beach enforces those building code regulations which pertain to stormwater control. VI. PLANNED AND PROPOSED UTILITIES As a result of concerns over the reliance on ground absorption systems, the development and implementation of some sort of centralized wastewater treatment system has become an important planning issue for the Town and the surrounding area. There currently exist plans to construct a sewer system for the Sunset Beach-Calabash ' area, which will provide sewer and related services to a 45-square mile section of Brunswick County. The proposed project is managed by the South Brunswick Water & Sewer Authority which consists of representatives from the Towns of Sunset Beach and ' Calabash, along with Brunswick County. Sunset Beach voters endorsed a central sewer system through a bond referendum which passed on April 5, 1994, approving a $5 million dollar bond issue. However, the Town has no plans of issuing the $5 million in sewer ' bonds approved by voters, but instead was seeking a vote of commitment for or against sewer. Anticipated funds include a $3.8 million loan from the North Carolina State Revolving Loan Fund, a $5 million North Carolina Clean Water Bond Loan, and $26.1 ' million in revenue bonds, which would be recouped through user fees. Currently, the plan is for the Towns of Sunset Beach and Calabash to each undertake an initial Phase I-A sewer program. The remainder of Phase I and Phase II could be accomplished by the Towns individually or the Water and Sewer Authority. An initial treatment facility with a capacity of around 2.5 million gallons per day (MGD) is ' envisioned. The effluent from the treatment facilities would be reused, primarily for golf course irrigation. Amore detailed description of the proposed facility can be found in The Financial Feasibility Report for Sanitary Sewer System Implementation Program ' Phases I and II (Powell Associates, 1993x). There has been some conjecture regarding the necessity of attaching the sewer line to .the bridge, creating the impression that sewer service could not be provided unless the budge was constructed. However, this is not the case. On March 5, 1990, the Town of Sunset Beach unanimously adopted a resolution urging that NCDOT engineers design ' the new bridge to allow for attachment of water and sewer lines. On March 26, 1990 NCDOT decided that it would not be feasible to attach water and sewer lines to the structure. The Town therefore withdrew its request by resolution dated April 2, 1990 (Mullen et al vs. Skinner, 1990). In addition, due to scheduling considerations in conjunction with deadlines for the sewer loan applications versus the actual completion of a new bridge, it is not feasible to consider attachment of the sewer line to the bridge. Therefore, this option was not considered by the engineering consultant charged with developing the sewer program and cost estimates for this option were not developed (J. Billups, P.E., 1994). VII. GENERAL DISCUSSION AND BACKGROUND INFORMATION The formal effort to develop a central sewer system came about in part as a result of a Comprehensive Wastewater Study prepared for the Town of Sunset Beach (Powell Associates Inc. & Piedmont Olson Hensley, 1992). This study identified the potential ' need for the provision of a central wastewater treatment facility based on the following factors: (1) Public opinion, as documented in the 1986 and 1992 Land Use Plan Update for the Town, (2) Documented septic tank system failures throughout the Planning Area ' (the Towns of Sunset Beach and Calabash, their Extraterritorial Jurisdictional boundaries, and likely adjacent areas of growth) and septic tank operational problems identified primarily on the island and within the Sea Trail Plantation Community, (3) ' Potential for environmental enhancement of sensitive adjacent shellfish waters through elimination of both septic tank and surface water runoff pollution sources, (4) Increased reliance throughout the Planning Area on alternative sewer systems for individual lots, ' (5) Requests for sewer service by individual and multiple lot owners for which lots the Brunswick County Health Department has denied septic tank permits. ~ ' This study further concluded that: (1) There is a present environmental hazard associated with failing septic systems, (2) There is a present environmental hazard associated with ' the lack of an effective stormwater management program, (3) There is a present environmental hazard associated with pollution from nutrients applied to golf courses for fertilization purposes being allowed to flow directly into adjacent streams and other ' water courses, (4) Existing state regulations governing the installation of on-site sewer systems may not afford adequate protection of ground water and surface water quality, (5) Surficial water supply aquifers are diminishing in terms of both quantity and quality, ' (6) Septic tank systems, particularly on the island of Sunset Beach, are being used at flow rates far in excess of their design capacities, (7) Building sites exist for which the Brunswick County Health Department will not issue septic tank permits. ' Powell Associates has conducted ev s eral studies of the area and concluded that septic tank systems were having an adverse impact on both groundwater and estuarine water quality on and around the island of Sunset Beach. This was reflected by increased levels of fecal coliform and other constituents of wastewater (Powell Associates, 1993b). ' There are basically three factors that contribute to groundwater and estuarine water quality. The first involves high groundwater table conditions, such as those that exist on the island. The effluent may not have time to be "treated" before coming into contact with the groundwater. A 1989 study prepared for the North Carolina Division of Coastal Management by Thomas P. Augspurger entitled "Assessment of Coastal North Carolina ' Domestic Wastewater Disposal Alternatives" states "that a preponderance of evidence suggests that the 30 centimeter separation (current state minimum) between septic drain line bottoms and the seasonally high water table does not ensure adequate aerobic conditions to properly treat domestic wastewater" (Powell Associates, 1993b). The second factor is the nature of the soils. Excessively permeable coarse grained soils, ' such as those found on the island, are not effective in the removal of viruses from septic tank effluent. Finally, there is the population density factor. The North Carolina Division of Environmental Management recognizes the potential adverse impact of using septic tank systems in higher density areas (greater than 1,200 gallons of waste per acre, or greater ' than three residential units per acre) in the coastal region (Powell Associates, 1993b). This problem is prevalent on the island where lots are typically 5,000 square feet, resulting in a density of 8 units per acre. (It should be noted that the island portion of ' the Town of Sunset Beach includes two types of zoning: BR1 -oceanfront lots with a minimum size of 7,500 square feet; and BR2 -all other lots with a minimum size of 4,500 square feet. The island also has lots that were platted prior to when the zoning ' regulations went into effect.) ' There has been considerable discussion with regard to the provision of centralized sewer service fostering unwanted or uncontrolled development. While it is certainly true that sewer availability is a factor in augmenting growth, it is not the determining factor. ' Market forces exist outside the availability of sewer service. It is "likely that development will continue in Sunset Beach with or without a sewer system as long as ~ ' there is a demand for resort housing. If a centralized sewer system is not built, developers will find other ways to build on large tracts of land without septic tanks. For ' example, developers could build private package treatment plants as was done in the Colony multi-family development in Sunset Beach." (Hayes and Associates, 1994x) ' The control of development is better handled by formal guidance system mechanisms as opposed to restricting services which may be beneficial to the environment and human health. The Town of Sunset Beach utilizes several land use planning tools to manage ' and direct its growth. These include zoning and subdivision ordinances, capital improvement policies, and a Land Use Plan. There is also a permit program, administered by both the State and the Town, which regulates development in Areas of Environmental Concern. It is important to note that these factors, conditions, and conclusions were derived independently of the issue of the bridge and highlight the need for a centralized wastewater treatment system, regardless of the outcome of the proposed Sunset Beach ' bridge replacement project. VIII. STORMWATER MANAGEMENT ' A separate but related issue are those impacts to water quality associated with stormwater runoff. There is some debate as to which is a greater threat to water quality, the continued reliance on septic systems or uncontrolled runoff from development. In the 1992 Land Use Plan Update, stormwater runoff was identified as a major concern. One of several policy statements which were developed reads as follows; "The Town of Sunset Beach encourages the use of innovative systems which encourage the use of pervious or semipervious materials and the retention of natural- vegetation which functions as a filter which minimizes the rapid release of pollutants to coastal waters ' through stormwater runoff." Consequently, the Town of Sunset Beach supports the concept of a regional stormwater management plan. ' Discussions regarding the development of a centralized wastewater treatment system have also included the development of a comprehensive stormwater management program. The Comprehensive Wastewater Study report (Powell Associates & Piedmont ' Olson Hensley, 1992) also called for the preparation and implementation of a Master Stormwater Management Plan to minimize the pollution potential from future development activities, and to remediate existing pollution problems associated with ' stormwater runoff. Several elements have been identified which would comprise such a plan. These include the requirement of on-site retention and/or the treatment of stormwater from all new development. This would be implemented regardless of size, from single family homes ' to large scale development. A second element would require the .elimination or treatment of existing sources of runoff pollution. This would include paved areas which allow petroleum products to concentrate and runoff into adjacent waters as well as nutrients from fertilizers and pesticides. Currently, there is consideration of a Basin-Wide Stormwater Management Study for the communities in South Brunswick County, including the Town of Sunset Beach (Powell ' Associates, 1993c). Within the vicinity of Sunset Beach, the waters of the Intracoastal Waterway and Calabash Creek are designated as Primary Nursery Areas by the North Carolina Marine Fisheries Commission. These are waters which correspond to the SA classification as defined by the North Carolina Department of Environment, Health, and Natural ' Resources as "tidal salt water used for shellfishing, primary recreation, aquatic life propagation and survival, fishing, wildlife, and secondary recreation." However, these waters have been currently closed to shellfish harvesting by the North Carolina Division of Marine Fisheries. Again, these conditions exist now and further study is warranted irrespective of the bridge replacement. This is especially true on the mainland, where growth has been significant during the past ten years. ' With respect to the bridge replacement, all of the current alternatives will result in short term impacts to water quality. Construction of the structure within the limits of open water will likely result in some impacts associated with dredging, pile driving or other forms of excavation connected to bridge construction. Any type of dredging or disruption of the substrate will likely cause temporary increases in turbidity. This could result in potential decreases in dissolved oxygen levels in the immediate area of construction activity. ' Direct impacts from runoff from the bridge may also occur. This can be mitigated during design and construction through collection of Stormwater runoff into approved water quality settlement systems. Various types of Stormwater collection and treatment ' systems will be investigated to determine the most economical alternative that meets NCDEHNR stormwater quality certification requirements. ' Long term impacts are expected to be minimal. All of the current alternatives are associated with the regular dredging of the Intracoastal Waterway for vessel traffic. Stringent application of best management practices (BMP's) and other sedimentation ' control measures must be implemented adjacent to coastal waters. ' IX. CONCLUSION Several studies have now been completed regarding various impacts that will result from ' the bridge replacement project. In a economic study prepared by Apogee Research, Inc., the conclusion was reached that ' the primary driving forces for mainland development are essentially independent of the ease or difficulty of access to Sunset Beach Island (Apogee, 1994). An analysis of the impacts of bridge replacements for Holden Beach and Ocean Isle Beach, prepared by Hayes and Associates, concluded that the type of bridge access did ' not greatly influence the rate or character of development on the islands (Hayes and Associates, 1994b). Therefore, it is reasonable to assume that a bridge replacement will not necessarily be the driving factor for rate or type of development with respect to Sunset Beach. Other factors that may influence the development of the Sunset Beach island include availability of sewer service, zoning, land use and regulations imposed by CAMA. It can be stated with a reasonable de ree of confidence that those issues concernin g g water quality and wastewater needs, associated with Sunset Beach and the surrounding area, are independent of the type of access provided to Sunset Beach. 1 ~ A ' REFERENCES 1 Apogee Research, Inc., 1994. Economic Impact Analysis. Prepared for the North Carolina Department of Transportation. Billups, J., 1994. Personal communication. ' Hayes and Associates, 1994x. Phase I Land Use Impact Report. Prepared for the North Carolina Department of Transportation. Hayes and Associates, 1993. Town of Sunset Beach, Land Use Plan Update 1992. Hayes and Associates, 1994b. The Induced Impact on Land Use as The Result of High Rise Bridge Replacement at Holden Beach and Ocean Isle Beach, NC. Prepared for the North Carolina Department of Transportation. ' Hayes and Associates, 1994c. Phase I Social Impact Report. Prepared for the North Carolina Department of Transportation. ' Mullen et al vs. Skinner, 1990. Memorandum Opinion, U.S. District Court, Eastern District of North Carolina, No. 90-547-CIV-S-BR, November 19, 1990. ' North Carolina Department of Transportation, 1992. Sunset Beach Bridge Replacement Study Scoping Report/Comments Secmmary Working Paper. ' Powell Associates of NMB, Inc. & Piedmont Olsen Hensley, 1992. Comprehensive Wastewater Study, Town of Sunset Beach. ' Powell Associates of NMB, Inc., 1993x. Soccth Brunswick Water & Sewer Authority and Town of Calabash & Sicnset Beach Financial Feasibility Report for Sanitary Sewer System Implementation Program (Phases I & II). Powell Associates of NMB, Inc., 1993b. Demonstration of Impact or Non-Impact of Septic Tanks on Groundwater and Surface Water Quality on and Around the Island of Sunset Beach. ' Powell Associates of NMB, Inc., 1993c. Outline Of Proposed South Brunswick Environmental Management Program. 1 ,~.~ ~ z \ ' S ~. \ -_ ~~ ~ I~~ ~~ _ _~. J I fnMO, / l ~ v / 1 r...a.f~'y, t wMnfa.. ; `\ B R U N 5 W 1` ~1 / ~ ~.~ ~! ~ ~ ~ ~.~~ e.IM 1 1 i ~ Swaj ,*~~I ~01.~ SMINIie i~ ',~~f lfM1 ELM ~I si I ~ I SAM r f 1I-- - • f / f MONM ~q lon - M ~ Of1M IY ~iw ~1ftl1 ~ `L ffftll:~ !WM ,y ~:~ PROJECT: 8.2230101 B-682 BRUNSWICK CO. REPLACEMENT OF BRIDGE OVER INTRACOASTAL WATERWAY ON SR 1172 AT SUNSET BEACH ATTACHMENT A 1 1 1