(A) Objective.
(1) It is the objective of this chapter to protect the physical and ecological integrity of waterways from surrounding upland activities. Aquatic buffers protect the integrity in the following ways:
(a) Filtering excess amounts of sediment, organic material, nutrients and other chemicals;
(b) Providing flood protection;
(c) Reducing storm water runoff velocities;
(d) Protecting channel bank areas from scour and erosion;
(e) Providing shade for cooling adjacent water, which allows waters to hold a great level of dissolved oxygen; and
(f) Providing leaf litter and large woody debris important to aquatic organisms.
(2) Aquatic buffers are most effective when storm water runoff is flowing into and through the buffer as shallow sheet flow, rather than in a concentrated form. Therefore, it is critical that the design of any development include best management practices, to the maximum extent practical, that will result in storm water runoff flowing into and through the aquatic buffer as shallow sheet flow.
(B) Applicability. This chapter shall apply to all new developments, modifications to existing developments and/or redevelopments within the city, except for the following:
(1) Development, modifications to existing development and/or redevelopment which prior to the effective date of the ordinance comprising this chapter;
(1) Is covered by a valid, unexpired site plan which has been issued a land disturbance; or
(2) Is covered by a valid, unexpired building permit.
(C) Width requirements for aquatic construction buffers. The aquatic buffer widths shall be calculated as follows:
(1) Aquatic construction buffer-zone requirements for discharges into impaired or high quality 303d listed streams must follow the state general construction permit requirement for these streams. (Refer to State NPDES permit § 4.4.2) http://www.state.tn.us/environment/wpc/stormh20/.
(2) For a non-303(d) listed, the width of aquatic construction buffer zone for a stream should be an average of 25 feet from the disturbed area to the stream bank.
(3) The aquatic construction buffer adjacent to delineated wetlands and springs shall extend an average of 25 feet perpendicular beyond the edges of the delineated wetlands and springs.
(D) Design standards for aquatic construction buffers.
(1) The aquatic construction buffer area is a mature strip of undisturbed native vegetation (either original or re-established) that can provide erosion control to the stream during construction. If an aquatic construction buffer area must be removed during construction then an appropriate width aquatic buffer must be replaced. A planting plan shall be required. A planting plan shall be submitted to the city for approval and will comply with the following:
(a) All planting plans shall be drawn at a scale of not less than one inch equals 20 feet for small tracts and one inch equals 50 feet for large tracts on 24-inch by 36-inch sheets;
(b) A minimum of two complete sets of planting plans shall be submitted at the time of application. Also, one reduced copy of a complete planting plan on a sheet(s) no larger than 11 inches by 17 inches shall also be submitted; and
(c) The planting plan shall include a "plant schedule"which lists the number and common and botanical name(s) of all existing and proposed plantings. The "plant schedule" shall also list the height, spread and where applicable, the caliper of all new plantings at the time of planting.
(2) Establishment of a aquatic construction buffer must adhere to the following conditions and be shown on the planting plan:
(a) Stream banks must be planted with native vegetation that represents both woody (trees and shrubs) and herbaceous species appropriate to the site. Density shall depend on there-vegetation technique to be used and existing site conditions;
(b) No trees shall be planted in a utility district easement;
(c) No species may comprise more than one-third of the total planted trees or shrubs;
(d) Seedlings/trees must be guaranteed at a 75% survivorship; and
(e) Invasive species must be removed.
(E) Management and maintenance of aquatic construction buffers.
(1) Management of the aquatic construction buffer during construction includes specific limitations on alteration of the natural conditions. The following practices and activities are restricted within the aquatic construction buffer, except with prior approval by the city:
(a) Clearing or grubbing of existing vegetation; and
(b) Use, storage or application of pesticides, herbicides and fertilizers.
(2) The following structures, practices and activities are permitted in the aquatic construction buffer subject to the prior approval by the city and the following specific design or maintenance features:
(a) Crossings (road and utilities); provided, the following criteria are followed.
1. Aquatic resource alteration permit must be obtained from State Department of Environment and Conservation if a stream crossing is necessary.
2. The width of the crossing should be minimum width and as perpendicular to the stream as possible.
(b) Paths and greenways, provided the design and location are approved by the city;
(c) Individual trees within the aquatic construction buffer may be removed if in danger of falling, causing damage to dwellings or other structures, causing blockage of the stream, standing in the path of a proposed water or sewer main, or the roots of the tree are penetrating or in danger of penetrating a sewer line at a joint of pipe connection. The root wad or stump should be left in place, where feasible, to maintain soil stability; and
(d) Removal of invasive species and replacement with approved native species.
(3) Aquatic construction buffers shall count toward open space reservation requirements.
(4) Aquatic construction buffers shall be left in a stabilized condition upon completion of the development and construction. The vegetative condition of the entire aquatic construction buffer must be monitored and landscaping or stabilization performed to repair erosion, damaged vegetation or other problems identified. Only native vegetation may be used in conjunction with stabilization activities. Subsequent permits, such as grading, and building, may be with held if, after written notification, required landscaping or landscaping to be preserved is not properly maintained. All landscaping or stabilization activities within the aquatic construction buffer must have prior approval by the city. In addition, performing work in and around waters of the state may require coverage under a state and possibly a federal permit.
(F) Water pollution hazards. The following land uses and/or activities are designated as potential water pollution hazards. Adequate containment systems to prevent runoff must be set up and these materials must be set back from any water body by the distance indicated below:
(1) Storage of hazardous substances: 150 feet;
(2) Above or below ground petroleum storage facilities: 150 feet; and
(3) Land application of biosolids: 100 feet or a distance as required by 40 C.F.R. part 503, whichever is greater.
(G) Conflict with other regulations. Where the standards and management requirements of this aquatic construction buffer ordinance are in conflict with other laws, regulations or ordinances regarding streams, steep slopes, credible soils, wetlands, floodplains, timber harvesting, land disturbance activities, Water Resource Habitat Conservation Plan, city's Aquatic Construction Buffer Map or other environmental protective measures, the more restrictive requirements shall apply.
(Ord. 1167, passed 4-24-2008)