Chapter 14.15
ON-SITE STORMWATER DRAINAGE
Sections:
14.15.030 Submission of drainage plan.
14.15.040 Contents of drainage plan.
14.15.050 Mandatory requirements for all drainage improvements.
14.15.060 Development in critical flood, drainage and/or erosion areas.
14.15.070 Establishment of regional facilities.
14.15.080 Temporary erosion controls.
14.15.100 Review and approval of plans.
14.15.120 Bonds and liability insurance required.
14.15.130 City assumption of maintenance.
14.15.140 Retroactivity relating to city maintenance of drainage facilities.
14.15.150 Maintenance of drainage facilities by owner.
14.15.160 Applicability to governmental entities.
14.15.010 Purposes.
This chapter is necessary in order to minimize water quality degradation by preventing the siltation of the city’s water bodies; to protect property owners adjacent to developing land from increased runoff rates which could cause erosion of abutting property; to promote sound development policies which respect and preserve the city’s watercourses; to insure the safety of the city streets and rights-of-way; and to decrease surface water damage to public and private property. (Ord. 398 § 1 (part), 1991)
14.15.020 Definitions.
A. “Comprehensive drainage plan” means a detailed analysis adopted by the city which compares the capabilities and needs for runoff accommodation due to various combinations of development, land use, structural and nonstructural management alternatives. The plan recommends the form, location, and extent of quantity and quality control measures which would satisfy legal constraints, water quality standards and community standards and identifies the institutional and funding requirements for plan implementation.
B. “Computations” means calculations, including coefficients and other pertinent data made to determine the drainage plan with flow of water given in cubic feet per second (cfs).
C. “Department” means the public works department of the city.
D. “Design storm” refers to that rainfall event which is selected by the department for purposes of design. The minimum design shall be for a ten-year return period storm, unless design discharge of the watershed exceeds twenty cfs, in which case the minimum design shall be for a twenty-five-year return period storm. Intensity/duration chart used in determining runoff shall be that as published by the U.S. Weather Bureau for Bridgeport.
E. “Development coverage” means all developed surface areas within the subject property including but not limited to rooftops, driveways, carports, accessory buildings and parking areas.
F. “Drainage area” means the watershed (acreage) contributing surface water runoff to and including the subject property.
G. “Drainage plan” means a plan for receiving, handling and transporting surface water within the subject property.
H. “Engineer” means the city engineer or public works director of Bridgeport.
I. “Peak discharge” means the maximum surface water runoff rate (cfs) determined for the design storm frequency.
J. “Procedures manual” means the manual of technical and administrative procedures and requirements adopted by the city which delineates methods to be used, the level of detail of analysis required and other submitted requirements implementation of the provisions of this chapter.
K. “Receiving bodies of water” means facilities designed either to hold runoff for a short period of time, then releasing it to the natural watercourse, or to hold water for a considerable length of time and then consume it by evaporation, plant transpiration, or infiltration to the ground.
L. “Subject property” means the tract of land which is the subject of the permit and/or approval action. (Ord. 398 § 1 (part), 1991)
14.15.030 Submission of drainage plan.
A. A drainage plan, as defined in Section 14.15.040, shall be submitted with applications for any of the following permits and/or approvals:
1. Grading permit;
2. Shoreline substantial development permit;
3. Flood-control zone permit;
4. Preliminary subdivision approval;
5. Short subdivision approval where the property is located within or adjacent to the floodplain or a river or stream, or where the property contains natural drainage swales and/or natural retention areas which exceed one foot in depth;
6. Binding site plan approvals for mobile home parks, condominiums, planned unit developments, industrial parks and shopping centers;
7. Building permits where the permit relates to five thousand or more square feet of development coverage on the property;
8. Rezones and conditional use permits where it is determined by the city engineer that the proposed development will have a significant adverse impact upon storm drainage.
B. The same plan submitted during one permit/approval process may be subsequently submitted with further required applications. The plan shall be supplemented with additional information at the request of the department. (Ord. 398 § 1 (part), 1991)
14.15.040 Contents of drainage plan.
A. Preliminary Drainage Review. All persons applying for any of the permits and/or approvals referred to in Section 14.15.030 shall submit a simple site plan showing the character of the existing site, natural drainage features occurring upon or adjacent to the site, the amount of impervious surface contemplated by the requested development, and the proposed methods of complying with the mandatory drainage requirements of Section 14.15.050. Based upon review of said submittal by the compliance officer and/or engineer, further drainage plans may be waived for any proposed activity or development which:
1. Will not adversely impact the water quality conditions of any affected receiving bodies of water;
2. Will not alter the surface discharge location, alter the drainage pattern on adjoining properties, alter drainage patterns, increase the peak discharge, adversely increase runoff volume, or cause any other adverse effects in the drainage area; and
3. Will not alter the subsurface drainage patterns, flow rates, or discharge points, nor result in any significant adverse effects to property or residents.
B. Detailed Drainage Plans. For applications which do not receive a waiver pursuant to subsection (A) of this section, a detailed drainage plan shall be submitted for surface and pertinent subsurface water flows, entering, flowing within and leaving the subject property both during and after construction. The plan shall contain the following information:
1. Project description:
a. Legal description of the property,
b. Names, addresses and telephone numbers of owners and persons ordering work to be performed,
c. Copies of other permits and/or permit applications such as Department of Fish and Game hydraulic application, Corps of Engineers permits and others,
d. To the extent necessary to adequately evaluate the accuracy of computations, the description will show locations of existing or proposed buildings, structures, utilities and site improvements where the work is to be performed and the location of any existing building or structure on adjacent property which is within fifteen feet of the new work,
e. Elevations, dimensions, location, extent of the slopes of all work proposed to be done shown on a contour map shall show the existing and proposed contours of the land,
f. The existing and proposed vegetative cover, soils types including trees, shrubs, grasses shall be depicted on a map of the site,
g. Location of existing drainage features which transport water onto, across or from the site including natural creeks, swales, artificial channels, drains or culverts. Also locations of springs, or other subsurface water outlets as well as ponds, lakes, swamps or potholes shall also be shown on the contour maps;
2. Background computations for sizing drainage facilities:
a. Depiction of the drainage area on a topographical map with acreage indicated,
b. Indications of the peak discharge and amount of surface water currently entering and leaving the subject property,
c. Indication of the peak discharge and amount of runoff which will be generated with the subject property, if development is allowed to proceed,
d. Determination of the peak discharge and amount of water that will be generated by the design storm frequencies as specified by the department at various points on the subject property. (Ord. 398 § 1 (part), 1991)
14.15.050 Mandatory requirements for all drainage improvements.
A. Commencement of construction, grading or site alteration work under any of the permits or approvals listed in Section 14.15.030 shall not begin until such time as final approval of the drainage plan has been granted by the engineer.
B. Surface water entering the subject property shall be received at the naturally occurring location and surface water exiting the subject property shall be discharged at the natural location with adequate energy dissipators to minimize downstream damage and with no diversion at any of these points.
C. The peak discharge from the subject property may not be increased due to the proposed development; and shall not exceed .2 cubic feet per second per acre under design storm conditions, except for a property discharging directly to a major receiving water, or to a public storm drain which the engineer finds has sufficient capacity to carry existing and anticipated loads from the point of connection to a receiving body of water.
D. Retention/detention facilities must be provided in order to handle all surface water in excess of the allowed peak discharge.
E. Where open ditch construction is used to handle drainage within the subject property, a minimum of fifteen feet will be provided between any structures and the top of the bank of the defined channel.
1. In open channel work the water surface elevation will be indicated on the plan and profile drawings. The configuration of the finished grades constituting the banks of the open channel will also be shown on the drawings.
2. Proposed cross-section of the channel will be shown with stable side slopes. Side slopes will be three-to-one maximum unless paved or stabilized in some manner approved by the department.
3. The water surface elevation of the design flow will be indicated on the cross-section.
F. Where a closed system is used to handle drainage within the subject property, all structures will be a minimum of ten feet from the closed system.
G. The proposed measures for controlling runoff during construction including a statement indicating the proposed staging of all clearing, grading and building activities.
H. Drainage facilities shall be designed and constructed in accordance with city standards and as directed by the engineer.
I. Vegetation shall be established on areas disturbed or other locations on the site to protect watercourses from erosion, siltation or temperature increases.
J. Surface water exiting from the subject property shall have pollution control and oil separator devices installed at the discharge point from the subject property when draining parking lots of paved roadway surfaces or handling contaminated storm runoff.
K. Variances from any or all of the foregoing requirements may be granted by the city engineer for a good cause, upon consideration of the following:
1. Capacity of downstream facilities;
2. Acceptability of receiving bodies of water;
3. Possibility of adverse effects of retention;
4. Utility of regional retention facilities; and
5. Capability of maintaining the system. (Ord. 398 § 1 (part), 1991)
14.15.060 Development in critical flood, drainage and/or erosion areas.
Development which would increase the volume of discharge from the subject property shall not be permitted in areas where existing flooding, drainage, and/or erosion, conditions present an imminent likelihood of harm to the welfare and safety of the surrounding community, until such time as the community hazard is alleviated. Where application of the provisions of this section will deny all reasonable use of the property, the city engineer may waive the restrictions on development contained in this section; provided that the resulting development shall be subject to all of the remaining terms and conditions of this chapter. (Ord. 398 § 1 (part), 1991)
14.15.070 Establishment of regional facilities.
A. In the event that public benefits would accrue due to modification of the drainage plan for the subject property to better implement the recommendations of the comprehensive drainage plan, the engineer may recommend that the city should assume responsibility for the further design, construction, operation and maintenance of the drainage facilities, or any increment thereof, on the subject property. Such decision shall be made concurrently with review and approval of the plan.
B. In the event that the city decides to assume responsibility for all or any portion of the design, construction, operation and maintenance of the facilities, the applicant shall be required to contribute a prorated share to the estimated cost of the facilities; provided, that such share shall not exceed the estimated costs of improvements the applicant would otherwise have been required to install. The applicant may be required to supply additional information at the request of the engineer to aid in such determination by the city. (Ord. 398 § 1 (part), 1991)
14.15.080 Temporary erosion controls.
A. Control of erosion from general clearing, grading and other construction activities shall be implemented to prevent damage by sedimentation to streams, floodplains, watercourses, natural areas and property of others during the construction phase and prior to completion of the permanent erosion control facilities.
B. On-site drainage controls shall minimize erosion and return waters to the natural drainage course free of sedimentation or other pollution to the maximum extent feasible.
C. Erosion control measures or devices shall be employed by the applicant as necessary prior to the initiation of construction. The engineer may require additional control measures where existing methods are failing to adequately control erosion.
D. The Washington State Administrative Code, Chapter 173-201, Water Quality Standards of Water of the State of Washington (as amended) is incorporated herein by this reference. The water quality criteria and waste discharge limitations shall be enforced by the engineer in cooperation with the Department of Ecology, and violators will be subject to the city enforcement action in addition to any state enforcement action. The engineer may use Jackson Turbity units as measured with a Jackson Candle turbidimeter instead of nephelometric turbidimeter units monitoring of turbidity levels. (Ord. 398 § 1 (part), 1991)
14.15.090 Fees.
No fee shall be required for a preliminary drainage review. Where a detailed drainage plan is required there shall be a plan-check fee paid in advance in the amount of one hundred fifty dollars, and an inspection fee to reimburse the city for staff time spent on the site at the rate of fifteen dollars per hour with a minimum fee of thirty dollars per job. (Ord. 398 § 1 (part), 1991)
14.15.100 Review and approval of plans.
All storm drainage plans prepared in connection with any of the permits and/or approval listed in Section 14.15.030 shall be submitted for review approval by the engineer. (Ord. 398 § 1 (part), 1991)
14.15.110 Inspections.
A. The holder of any permit or approval issued subject to a detailed drainage plan shall arrange with the engineer for scheduling the following inspections:
1. Initial Inspection. Whenever work on the site preparation, grading, excavations, or fill is ready to be commenced, but in all cases prior thereto;
2. Rough Grading. When all rough grading has been completed;
3. Bury Inspection. Prior to burial of any underground drainage structure;
4. Finish Grading. When all work including installation of all drainage structures and other protective devices has been completed;
5. Planting. When erosion control planting shows active growth.
B. In some circumstances not all of the above inspections may be necessary. It shall be the discretion of the engineer to waive or combine any of the above inspections as dictated by conditions.
C. The engineer shall inspect the work and shall either approve the same or notify the applicant in writing in what respects there has been failure to comply with the requirements of the approved plan. Any portion of the work which does not comply shall be promptly corrected by the applicant. The engineer may make unscheduled site inspections to ensure compliance. Uncorrected violations will be subject to the provisions of Section 14.15.170. (Ord. 398 § 1 (part), 1991)
14.15.120 Bonds and liability insurance required.
The department is authorized to require all persons constructing retention/detention or other drainage treatment/abatement facilities to post surety or cash bonds. Where such persons have previously posted, or are required to post, other such bonds on the facility itself or on other construction related to the facility, such person may, with the permission of the engineer and to the extent allowable by law, combine all such bonds into a single bond; provided, that at no time shall the amount thus bonded be less than the total amount which would have been required in the form of separate bonds; and provided further, that such a bond shall on its face clearly delineate those separate bonds which it is intended to replace.
A. Construction Bond. Prior to commencing construction, the person constructing the facility shall post a construction bond in an amount sufficient to cover the cost of conforming said construction with the approved drainage plans. Alternatively, an equivalent cash deposit to an escrow account administered by a local account bank may be allowed, at the city’s option.
B. Maintenance Bond. After satisfactory completion of the facilities and release of the construction bond by the city, the person constructing the facility shall commence a one-year period of satisfactory maintenance of the facility. A cash bond to be used at the discretion of the engineer to correct deficiencies in said maintenance affecting public health, safety and welfare must be posted and maintained throughout the one-year maintenance period. The amount of the cash bond shall be determined by the engineer. In addition, a surety bond or cash bond to cover the cost of design defects or failures in workmanship shall also be posted and maintained through the one-year maintenance period. Alternatively, an equivalent cash deposit to an escrow account administered by a local account bank may be allowed, at the city’s option.
C. Liability Policy. The person constructing the facility shall maintain a liability policy in an amount to be determined by the city which shall name the city as an additional insured and which shall protect the city from any liability for any accident, negligence, failure of the facility, or any other liability whatsoever, relating to the construction or maintenance of the facility. The liability policy shall be maintained for the duration of the facility by the owner of the facility; provided that in the case of facilities assumed by the city for maintenance pursuant to Section 14.15.130, the liability policy shall be terminated when the city maintenance responsibility commences. (Ord. 398 § 1 (part), 1991)
14.15.130 City assumption of maintenance.
The city may assume the maintenance of retention/detention facilities after the expiration of the one-year maintenance period if:
A. All of the requirements of this chapter have been fully complied with;
B. The facilities have been inspected and approved by the department after the first year of operation;
C. The surety bond required in Section 14.15.120 has been extended for one year, covering the city’s first year of maintenance;
D. All necessary easements entitling the city to properly maintain the facility have been conveyed to the city. (Ord. 398 § 1 (part), 1991)
14.15.140 Retroactivity relating to city maintenance of drainage facilities.
If any person constructing retention/detention facilities and/or receiving approval of drainage plans prior to the effective date of this chapter demonstrates, to the city’s satisfaction, total compliance with the requirements of this chapter, the city may, after inspection, approval and acknowledgement of the proper posting of the required bonds as specified in Section 14.15.120, assume maintenance of the facilities. (Ord. 398 § 1 (part), 1991)
14.15.150 Maintenance of drainage facilities by owner.
In the event that the city elects not to assume the operation and maintenance responsibility for the facilities, it shall be the responsibility of the owner of the property, his heirs, successors and assigns, to operate, maintain, repair and replace the facilities in continuous compliance with the standards and specifications of the department. The engineer shall have authority to periodically enter upon the property and inspect the facilities to insure such compliance. (Ord. 398 § 1 (part), 1991)
14.15.160 Applicability to governmental entities.
All municipal corporations and governmental entities shall be required to submit a drainage plan and comply with the terms of this chapter when developing and/or improving land within the incorporated areas of the city or within adjacent areas which may affect the city. (Ord. 398 § 1 (part), 1991)
14.15.170 Enforcement.
A. Nuisance. Any structure or condition which violates any provision of this chapter shall be and the same is declared to be unlawful and a public nuisance and may be abated as such.
B. Cumulative Civil Penalty. In addition to or as an alternative to any other penalty provided in this chapter or by law, any person who violates the provisions of this title, the procedures manual, or an approved detailed drainage plan, shall incur a cumulative civil penalty in the amount of one hundred dollars per day from the date set for correction, pursuant to subsection (C) of this section, until the violation is corrected.
C. Notice of Violation—Assessment of Penalty. Whenever the engineer has found or determined that a violation is occurring the compliance officer is authorized to issue a notice a violation directed to the property owner or occupant.
1. The notice of violation shall contain:
a. The name and address of the violator, if known;
b. The street address, when available, or a legal description sufficient for identification of the building, structure, premises, or land upon or within which the violation is occurring;
c. A statement of the nature of such violation(s);
d. A statement of the action required to be taken as determined by the engineer and a date for correction, which shall be not less than three weeks from the date of service of the notice of violation, unless the engineer has determined the violation to be hazardous and to require immediate corrective action or unless the corrective action constitutes a temporary erosion control measure;
e. A statement that a cumulative civil penalty in the amount of one hundred dollars per day shall be assessed against the person to whom the notice of violation is directed for each and every day following the date set for correction on which the violation continues; and
f. A statement that the engineer’s determination of violation may be appealed to the city council by filing written notice of appeal, in duplicate, with the city clerk within twenty days of service of the notice of violation. The per diem civil penalty shall not accrue during the pendency of such administrative appeal unless the violation was determined by the engineer to be hazardous and to require immediate corrective action or was determined by the engineer to constitute a temporary erosion control measure.
2. The notice of violation shall be served upon the person(s) to whom it is directed either personally, or by mailing a copy of the notice of violation by certified mail, postage prepaid, return receipt requested, to such person at his last known address. Proof of personal service shall be made at the time of service by a written declaration under penalty of perjury executed by the person affecting service, declaring time, date and the manner by which service was made.
D. Collection of Civil Penalty. The civil penalty constitutes a personal obligation of the person(s) to whom the notice of violation is directed. The city attorney, on behalf of the city, is authorized to collect the civil penalty by use of appropriate legal remedies, the seeking or granting of which shall neither stay nor terminate the accrual of additional per diem penalties so long as the violation continues.
E. Compromise Settlement and Disposition of Suits. The engineer and the city attorney are authorized to enter into negotiations with the parties or their legal representatives named in a lawsuit for the collection of civil penalties, to negotiate a settlement, compromise or otherwise dispose of a lawsuit when to do so will be in the best interests of the city, provided that a report shall be submitted to the city council in any instance when a compromise settlement is negotiated. (Ord. 398 § 1 (part), 1991)