(A) General. The following activities must be authorized by permit, except for excavation for permitted structure, drives, sewer systems and parking areas:
(1) Grading and filling disturbing an area greater than one acre;
(2) Grading and filling in the Shore Impact Zone; and
(3) Any alterations of the natural topography when the slope of the land is toward a public water or watercourse involving the movement of more than ten cubic yards of material in a bluff or Shore Impact Zone or more than 50 cubic yards of material anywhere else within a shoreland area.
(B) Conditions. The following conditions shall apply.
(1) The smallest amount of bare ground is exposed for as short a time as feasible.
(2) Four inches of topsoil is placed, temporary ground cover such as mulch is used and permanent ground cover such as sod is planted.
(3) Methods to prevent erosion and trap sediment are employed.
(4) Fill is stabilized to acceptable engineering standards and must not create an unstable slope.
(5) Plans to place fill or excavated material on steep slopes must be reviewed by a qualified professional for continued slope stability and must not create finished slopes of 30% or greater.
(6) Fill or excavated material must not be placed in bluff impact zones.
(7) Fill placed in a public water below the ordinary high water mark requires a DNR waters permit and a Corps of Engineers permit.
(8) Excavation in the bed of public waters requires a DNR waters permit and a Corps of Engineers permit.
(9) Only clean fill consisting of sand, gravel or rock will be allowed where contact with water is anticipated. Mineral soil may be allowed elsewhere.
(10) Alterations to topography must only be allowed if they are accessory to permitted or conditional uses and do not adversely affect adjacent or nearby properties.
(11) When applicable, the above conditions shall be consistent with those provided within this division (B), in addition to those required by Mississippi Headwaters Board, the state’s DNR and the Army Corps of Engineers.
(C) Wetlands. Grading or filling in any protected wetland is prohibited unless authorized by federal, state, county and local permitting agencies.
(D) Public waters. Connections to public waters of boat slips, canals, lagoons, harbors and similar inland excavations are prohibited.
(E) Riprap. The city encourages the use of riprap only as a last resort to control shoreline erosion. Other methods should be used, including the planting of native, deep rooted vegetation. If riprap has been found to be the only tool available, riprap installation shall have the following standards.
(1) Gradation. A well-graded mixture of rock sizes should be used instead of one uniform size.
(2) Quality of stone. Riprap must be durable so that freeze/thaw cycles do not decompose it in a shore time; most igneous stones such as granite have suitable durability.
(3) Riprap depth. The thickness of riprap layers should be at least two times the maximum stone diameter.
(4) Vegetation.
(a) Existing vegetation on the shoreline and in the water should be maintained without disturbance.
(b) All bare soil on the slope above the riprap should be stabilized with seed and mulch, or sod.
(c) Wooded, deep rooted vegetation should be planted among the riprap to help stabilize and create wildlife habitat.
(5) Filter material. Filter material is usually required between riprap and the underlying soil surface to prevent soil from moving through the riprap; a filter cloth material or a layer of gravel is usually used for the filter.
(a) Leaching protection. Leaching can be controlled by installing a riprap gradation small enough to act as a filter against the channel base material, or a protective filter can be installed between the riprap and the base material.
(b) Riprap limits. The riprap should extend for a maximum flow depth, or to a point where vegetation will be satisfactory to control erosion.
(c) Curves. Riprap should extend to five times the bottom width upstream and downstream of the beginning and ending of the curve as well as the entire curved section.
(d) Riprap size. The size of riprap to be installed depends on site-specific conditions.
(e) Riprap prohibitions. Slopes on which riprap is used to stabilize shorelines shall be no steeper than two to one.
(6) Maintenance. Inspections should be made of all sites immediately after the first rainfall following installation of riprap. This is particularly important in areas where riprap that is displaced during the storm would impact culverts. Thereafter, riprapped sites should be checked following large storms, especially those which are near or exceed the storm frequency used in the design. Displaced riprap should be removed from its downstream location and new riprap placed according to the specifications above.
(Ord. 332, passed 5-19-2008) Penalty, see § 152.999