For purposes of this chapter, the following words and phrases shall have the meanings respectively ascribed to them by this section:
“CBS”
means city and borough of Sitka.
“Design storm”
means a rainfall event of chosen intensity and duration selected for a storm drainage analysis or system design, and is usually expressed as having a statistical probability of recurrence, such as once in every five, 10, 50, or 100 years on average. A 100-year storm has a one percent probability of occurring in a given year.
“Designated special drainage use areas”
means areas within the city which have been designated as critical to the passage of stormwater runoff from upland origins to salt water discharge.
“Development”
means, but is not limited to, buildings, bridges, road building, grading, land-filling, excavations, utilities or other capital improvements and other land use changes that add impervious area.
“Director of public works”
means either the director of the city’s department of public works or the director’s designee.
“Drainage basins”
means those lands draining to a common watercourse or outlet including the headwaters of said watercourse.
“Drainage system”
means the system of facilities for collecting and conveying stormwater runoff, including streams, pipelines, channels, ditches, lakes, wetlands, and other drainage structures and appurtenances, natural and manmade.
“Erosion”
means the process by which stormwater dislodges and transports soil and other materials.
“Excavation”
means the physical, manmade removal of earth material.
“Floodplain”
means the low-lying area adjacent to a watercourse onto which excessive water flows during periods of prolonged and intensive precipitation. The floodplain for a particular watercourse is a geographical area flooded by a storm of specified recurrence interval.
“Grading”
means any act which changes the elevation of the ground surface.
“Impervious”
means impenetrable – completely resisting the entrance of liquids.
“Peak discharge”
means the maximum rate of stormwater runoff at a particular point determined for the design storm.
“Public drainage system”
means all drainage systems lying within dedicated public easements and rights-of-way or other public lands, and watercourses through private lands which serve as integral parts of drainage systems which convey surface water from streets or public lands, or which provide common drainage from more than one parcel.
“Recurrence interval”
is the estimated interval of time between storms of a given intensity and duration.
“Sediment”
means waterborne particles, graded or undefined, occurring by erosive action.
“Sedimentation”
means the deposition of debris and soil sediment displaced by erosion and transported by runoff.
“Storm sewer”
means an underground conduit to convey discharges to an outfall point.
“Stream”
means a surface water route generally consisting of a channel with bed, banks, or sides, in which surface waters flow in draining from higher to lower land, both perennial and intervening; the channel and intervening artificial components, excluding flows which do not persist more than 24 hours after cessation of rainfall at some time of the year.
“Watercourse”
means the course or route followed by waters draining from the land, generally formed by nature.
(S.G.C. 15.07.010; Ord. 15-07 § 4, 2015)
A. 
This chapter is established to promote, protect, and preserve the public interest by regulating the planning, construction, and maintenance of public and private storm drainage systems within the CBS.
B. 
The specific objectives of this chapter include but are not limited to:
1. 
The prevention and abatement of flooding and runoff-related property damage, nuisances, or hazards;
2. 
The prevention of adverse effects of alterations in surface water quantities, locations, and flow patterns;
3. 
The prevention of actions or practices which would reduce the ability of the public drainage system to convey storm drainage at its intended capacity;
4. 
The establishment of minimum standards for planning, construction, and maintenance of storm drainage improvements within the CBS; and
5. 
The establishment of administrative procedures for permits, plan reviews, and construction quality control for grading or drainage improvements significantly affecting the public drainage system.
C. 
This chapter is intended to promote the health, safety and welfare of the public and nothing herein is intended to or shall be deemed to create a duty in the CBS to protect or promote the interests of any particular person or class of persons. The existence of these regulations or any failure, refusal or omission of the CBS to enforce any provision herein shall not prevent, supplant or affect the right of any person affected by the clearing, grading, or drainage operations of another to invoke such private remedies as may be available against such other person.
(S.G.C. 15.07.020; Ord. 15-07 § 4, 2015)
A. 
This chapter shall apply to all property within the CBS, both privately and publicly owned.
B. 
To the extent permitted by law, governmental entities, including municipal corporations and their departments, government owned utilities, school districts, and agencies and departments of state and federal government, shall be subject to the provisions of this chapter.
C. 
Other CBS, state and federal laws and regulations may apply to storm drainage related matters within the CBS. Compliance with the provisions of this chapter does not guarantee compliance with such other requirements.
(S.G.C. 15.07.030; Ord. 15-07 § 4, 2015)
The director of public works is charged with the administration and enforcement of this chapter. The director is empowered to establish such administrative procedures and guidelines as are required in the execution of this authority.
(S.G.C. 15.07.040; Ord. 15-07 § 4, 2015)
A. 
Design and construction standards for storm drainage improvements within the CBS shall be prepared, maintained, and revised from time to time by the director of public works and made available in written form to the general public upon request.
B. 
Construction standards for storm drainage improvements are referred to as “City and Borough of Sitka Standard Specifications” and are hereby adopted as official CBS standards for design and construction of culverts, catch basins, drains, ditches, drainage inlets, and other ordinary drainage improvements.
C. 
Design standards for storm drainage improvements are referred to as “City and Borough of Sitka Stormwater Design Standards” and are hereby adopted as official CBS standards for the hydrologic and hydraulic design and sizing of culverts, drains, ditches, drainage inlets, and other ordinary drainage improvements.
D. 
Construction of drainage improvements in public rights-of-way, easements and areas for which drainage permits are required under the Sitka General Code shall be designed and constructed in compliance with standards adopted in this chapter.
E. 
The director of public works may revise and update the “City and Borough of Sitka Standard Specifications” or the “City and Borough of Sitka Stormwater Design Standards” to reflect changes in technology, new information concerning hydrologic or meteorological assumptions, changes in the type and availability of construction materials, and standards guidance from other governmental entities.
F. 
The director of public works may allow deviations from the “City and Borough of Sitka Standard Specifications” or the “City and Borough of Sitka Stormwater Design Standards” when he/she determines that drainage can be better accommodated by alternate design or construction methods, or when substitutions of alternate construction materials would not result in loss of essential function. A variance may also be granted by the director of public works when he/she finds that:
1. 
Downstream facilities have sufficient capacity under design conditions to safely convey the proposed runoff;
2. 
The quality of the receiving waters will be maintained;
3. 
There is minimal potential for adverse effects from the proposed runoff;
4. 
The proposed system can be maintained; and
5. 
The proposed system does not compromise the structural integrity of abutting roadways, foundations, or structures.
(S.G.C. 15.07.050; Ord. 15-07 § 4, 2015)
A. 
Areas within the CBS which are critical or may reasonably become critical to the passage of stormwater runoff from upland origins are hereby established as “designated special drainage use areas.” Critical areas are those in which existing or potential flooding, drainage, erosion, water quality, and/or instability conditions present a reasonable likelihood of harm to the welfare and safety of surrounding property, or to the integrity of surface water systems and resources.
B. 
Designated special drainage use areas may be identified and delineated on maps for purposes of this chapter. The director of public works shall be responsible for preparing, maintaining and updating maps of designated special drainage use area boundaries.
(S.G.C. 15.07.060; Ord. 15-07 § 4, 2015)