Chapter 142

STORMWATER MANAGEMENT

[HISTORY: Adopted by the Mayor and Council of the Town of Chestertown 6-25-1984 as Ord. No. 2-84. Amendments noted where applicable.]

GENERAL REFERENCES

Planning Commission -- See Ch. 25.

Building construction -- See Ch. 57.

Floodplain management -- See Ch. 81.

Grading and sediment control -- See Ch. 88.

Subdivision of land -- See Ch. 148.

Water and sewers -- See Ch. 164.

Zoning -- See Ch. 170.

~ 142-1. Legislative purpose; statutory authority and applicability.

A. Purpose. The purpose of this chapter is to protect, maintain and enhance public health and safety and general welfare by establishing minimum requirements and procedures to control the adverse impacts associated with increased stormwater runoff. Proper management of stormwater runoff will minimize damage to public and private property, reduce the effects of development on land and stream channel erosion, assist in the attainment and maintenance of water quality standards, reduce local flooding and maintain after development, as nearly as possible, the predevelopment runoff characteristics.

B. Authority; applicability of provisions; enforcement. The provisions of this chapter, pursuant to the Natural Resources Article, ~ 8-11A-02, of the Annotated Code of Maryland, 1983 Replacement Volume, are adopted under the authority of the Municipal Corporation Charter of Chestertown, Maryland, and shall apply to all development occurring within the incorporated area of the Town of Chestertown. The application of this chapter and the provisions expressed herein shall be the minimum stormwater management requirements and shall not be deemed a limitation or repeal of any other powers granted by state statute. The Mayor and Council of Chestertown shall be responsible for the coordination and enforcement of the provisions of this chapter.

~ 142-2. Definitions.

For the purposes of this chapter, the following definitions describe the meanings of the terms used in this chapter:

ADVERSE IMPACT -- Any deleterious effect on waters or wetlands, including their quality, quantity, surface area, species composition, aesthetics or usefulness for human or natural uses, which is or may potentially be harmful or injurious to human health, welfare, safety or property, to biological productivity, diversity or stability or which unreasonably interferes with the enjoyment of life or property, including outdoor recreation.

AGRICULTURAL LAND MANAGEMENT PRACTICES -- Those methods and procedures used in the cultivation of land in order to further crop and livestock production and conservation of related soil and water resources.

APPLICANT -- Any person, firm or governmental agency which executes the necessary forms to procure official approval of a project or a permit to carry out construction of a project.

AQUIFER -- A porous, water-bearing geologic formation, generally restricted to materials capable of yielding an appreciable supply of water.

CLEARING -- The removal of trees and brush from the land, but shall not include the ordinary mowing of grass.

DETENTION STRUCTURE -- A permanent structure for the temporary storage of runoff which is designed so as not to create a permanent pool of water.

DEVELOP LAND -- To change the runoff characteristics of a parcel of land in conjunction with residential, commercial, industrial or institutional construction or alteration.

DRAINAGE AREA -- That area contributing runoff to a single point, measured in a horizontal plane, which is enclosed by a ridge line.

EASEMENT -- A grant or reservation by the owner of land for the use of such land by others for a specific purpose or purposes and which must be included in the conveyance of land affected by such easement.

EXEMPTION -- Those land development activities that are not subject to the stormwater management requirements contained in this chapter.

FLOW ATTENUATION -- Prolonging the flow time of runoff to reduce the peak discharge.

GRADING -- Any act by which soil is cleared, stripped, stockpiled, excavated, scarified, filled or any combination thereof.

INFILTRATION -- The passage or movement of water into the soil surface.

OFF-SITE STORMWATER MANAGEMENT -- The design and construction of a facility necessary to control stormwater from more than one (1) development.

ON-SITE STORMWATER MANAGEMENT -- The design and construction of systems necessary to control stormwater within an immediate development.

POROUS PAVING -- An open-graded asphaltic or reticular concrete or other material which allows water to pass through it.

RETENTION STRUCTURE -- A permanent structure that provides for the storage of runoff by means of a permanent pool of water.

SEDIMENT -- Soils or other surficial materials transported or deposited by the action of wind, water, ice or gravity as a product of erosion.

SITE -- Any tract, lot or parcel of land or combination of tracts, lots or parcels of land which are in one (1) ownership or are contiguous and in diverse ownership where development is to be performed as part of a unit, subdivision or project.

STABILIZATION -- The prevention of soil movement by any vegetative and/or structural means.

STORMWATER MANAGEMENT:

A. For quantitative control, a system of vegetative and structural measures that control the increased volume and rate of surface runoff caused by man-made changes to the land.

B. For qualitative control, a system of vegetative, structural and other measures that reduce or eliminate pollutants that might otherwise be carried by surface runoff.

STORMWATER MANAGEMENT PLAN -- A set of drawings or other documents submitted by a person as a prerequisite to obtaining a stormwater management approval, which contain all of the information and specifications pertaining to stormwater management.

STRIPPING -- Any activity which removes the vegetative surface cover, including tree removal, clearing, grubbing and storage or removal of topsoil.

VARIANCE -- The modification of the minimum stormwater management requirements for specific circumstances where strict adherence to the requirements would result in unnecessary hardship and not fulfill the intent of this chapter.

WAIVER -- The relinquishment from stormwater management requirements by the Town of Chestertown for a specific development on a case-by-case review basis.

WATERCOURSE -- Any natural or artificial stream, river, creek, ditch, channel, canal, conduit, culvert, drain, waterway, gully, ravine or wash, in and including any area adjacent thereto, which is subject to inundation by reason of overflow or floodwater.

WATERSHED -- The total drainage area contributing runoff to a single point.

WETLANDS -- An area that has saturated soils or periodic high groundwater levels and vegetation adapted to wet conditions and periodic flooding.

~ 142-3. Control measures.

A. Control measures required prior to development. No person shall develop any land for residential, commercial, industrial or institutional uses without having provided for appropriate storm water management measures that control or manage runoff from such developments, except as provided in this section.

B. Exemptions. The following development activities are exempt from the provisions of this chapter and the requirements of providing stormwater management:

(1) Normally accepted agricultural land management activities.

(2) Additions or modifications to existing single-family detached residential structures.

(3) Developments that do not disturb over five thousand (5,000) square feet of land area.

(4) Land development activities which the Water Resources Administration determines will be regulated under specific state laws which provide for managing stormwater runoff.

(5) Residential developments consisting of single-family houses, each on a lot of two (2) acres or greater.

C. Waiver; eligibility. The Town of Chestertown may grant a waiver of the stormwater management requirements for the individual developments, provided that a written request is submitted by the applicant which contains descriptions, drawings and any other information that is necessary to evaluate the proposed development. A separate written waiver request shall be required in accordance with the provisions of this section if there are subsequent additions, extensions or modifications to a development receiving a waiver. Eligibility for a waiver shall be determined if the applicant can conclusively demonstrate that:

(1) The proposed development will not generate an increase of more than ten percent (10%) in the two-year predevelopment peak discharge rate and will not cause an adverse impact on the receiving wetland, watercourse or body of water;

(2) A site is completely surrounded by existing areas which are served by an existing network of public storm drainage systems of a capacity adequate to accommodate the runoff from the additional development;

(3) Provisions to control direct outfall to tidewater are provided when the first inch of rainfall is managed according to infiltration standards and specifications promulgated by the Water Resources Administration; or

(4) A high-water table exists on the site such that the potential health risks caused by retention of stormwater exceed the benefit of such retention for stormwater management purposes.

D. Variances. The Town of Chestertown may grant a written variance from any requirement of ~ 142-6 of this chapter if there are exceptional circumstances applicable to the site such that strict adherence to the provisions of this chapter will result in unnecessary hardship and not fulfill the intent of the chapter. A written request for variances shall be provided to the Town of Chestertown and shall state the specific variances sought and reasons for their granting. The Town of Chestertown shall not grant a variance unless and until sufficient specific reasons justifying the variance are provided by the person developing the land.

~ 142-4. Stormwater management plans.

A. Review and approval.

(1) A stormwater management plan or an application for a waiver shall be submitted to the Town of Chestertown by the developer for the review and approval of any proposed development, unless otherwise exempted. The stormwater management plan shall contain supporting computations, drawings and sufficient information describing the manner, location and type of measures with which stormwater runoff will be managed from the entire development. The Town of Chestertown shall review the plan to determine compliance with the requirements of this chapter prior to approval. The plan shall serve as the basis for all subsequent construction.

(2) Notification of approval or reasons for the disapproval or modification shall be given to the applicant within forty-five (45) days after submission of the completed stormwater plan. If a decision is not made within forty-five (45) days, the applicant shall be informed of the status of the review process and the anticipated completion date. The stormwater management plan shall be considered approved without the inclusion of the signature and date of signature of the Kent Soil Conservation District on the plan.

B. Contents. The developer is responsible for submitting a stormwater management plan which meets the design requirements provided by this chapter. The plan shall include sufficient information to evaluate the environmental characteristics of the affected areas, the potential impacts of the proposed development on water resources and the effectiveness and acceptability of measures proposed for managing stormwater runoff. The developer or builder shall certify on the drawings that all clearing, grading, drainage, construction and development shall be conducted in strict accordance with the plan. The minimum information submitted for support of a stormwater management plan or application for a waiver shall be as follows:

(1) Site characteristics.

(a) A topography survey showing existing and proposed contours, including the area necessary to determine a downstream analysis for the proposed stormwater management facility.

(b) A soils investigation, including borings for construction of small ponds and infiltration practices.

(c) A description of all watercourses, impoundments and wetlands on or adjacent to the site or into which stormwater flows.

(d) A delineation of one-hundred-year floodplains, if applicable.

(e) A structure classification (SCS Pond Standard 378).

(2) Computations.

(a) Hydrologic.

(b) Hydraulic.

(3) In addition to the information listed above, stormwater management design plans shall include the following:

(a) Stormwater management plans.

[1] A vicinity map.

[2] A drainage area map showing the watershed boundaries, drainage area and stormwater flow paths.

[3] Proposed improvements, including the location of buildings or other structures, impervious surfaces and storm drainage facilities, if applicable.

[4] The location of utilities.

[5] Structural details for all components of the proposed drainage systems and stormwater management facilities.

[6] Timing schedules and the sequence of development clearing, including stripping, rough grading, construction, final grading and vegetative stabilization.

[7] A maintenance schedule.

[8] Notes on drawings specifying materials to be used.

[9] Construction specifications.

[10] The location of easements.

(b) An estimate of stormwater management construction costs.

~ 142-5. Permit requirements; fee; suspension and revocation.

A. Prerequisites for permit issuance. A grading or building permit may not be issued for any parcel or lot unless a stormwater management plan has been approved or waived by the Town of Chestertown as meeting all the requirements of this chapter. Where appropriate, a building permit may not be issued without the following:

(1) Recorded easements for the stormwater management facility and easements to provide adequate access for inspection and maintenance of a public right-of-way.

(2) A recorded stormwater management maintenance agreement.

(3) Performance bond.

B. Fees. A nonrefundable permit fee will be collected at the time the stormwater management plan or application for waiver is submitted. The permit fee will provide for the cost of plan review, administration and management of the permitting process, and inspection of all projects subject to this chapter. A permit fee schedule shall be established by the Town of Chestertown based upon the relative complexity of the project, and such may be amended from time to time.

C. Suspension and revocation. Any grading or building permit issued by the Town of Chestertown may be suspended or revoked after written notice is given to the permittee for any of the following reasons:

(1) Any violation(s) of the conditions of the stormwater management plan approval.

(2) Changes in the site runoff characteristics upon which a waiver was granted.

(3) When construction is not in accordance with the approved plans.

(4) Noncompliance with a correction notice(s) or stop work order(s) issued for the construction of the stormwater management facility.

(5) When an immediate danger exists in a downstream area in the opinion of the Town of Chestertown.

D. Conditions of plan approval. In granting the plan approval, the Town of Chestertown may impose such conditions thereto as may be deemed necessary to ensure compliance with the provisions of this chapter and the preservation of the public health and safety.

~ 142-6. Criteria for control measures established; design standards.

A. Minimum control requirements.

(1) The minimum stormwater control requirements shall require that all developments provide management measures necessary to maintain the post-development peak discharges for a twenty-four-hour, two-year and ten-year frequency storm event at a level that is equal to or less than the respective twenty-four-hour, two-year and ten-year predevelopment peak discharge rates through stormwater management practices that control the volume, timing and rate of flows. Where runoff is discharged into an off-site stormwater management facility, the control requirements and procedures shall be in accordance with Subsection (3) of this section.

(2) Stormwater management and development plans, where applicable, shall be consistent with adopted and approved watershed management plans or flood management plans as approved by the Water Resources Administration in accordance with the Flood Control and Watershed Management Act of 1976 (Natural Resources Article, ~ 8-9A-01 et seq., of the Annotated Code of Maryland.

B. Stormwater management measures.

(1) Stormwater management measures shall be required to satisfy the minimum control requirements. The stormwater management practices to be utilized in developing a stormwater management plan shall be according to the following order of preference:

(a) Infiltration of runoff on site.

(b) Flow attenuation by use of open, vegetated swales and natural depressions.

(d) Stormwater detention structures.

(2) Infiltration practices shall be utilized to reduce volume increases to the extent possible as determined in accordance with infiltration standards and specifications established by the Water Resources Administration. A combination of successive practices may be used to achieve the applicable minimum control requirements. Justification shall be provided by the person developing land for rejecting each practice based on site conditions.

C. Specific design criteria.

(1) Infiltration systems shall be designed in accordance with standards and specifications that are developed or approved by the Water Resources Administration and shall meet the following requirements:

(a) Infiltration systems greater than three (3) feet deep shall be located at least ten (10) feet from a basement wall.

(b) Infiltration systems designed to handle runoff from commercial or industrial impervious parking areas shall be a minimum of one hundred (100) feet from any water supply well.

(c) Infiltration systems may not receive runoff until the entire contributory drainage area to the infiltration system has received final stabilization.

(d) The stormwater management facility design shall provide an overflow system with measures to prod vide a nonerosive velocity of flow along its length and at the outfall.

(2) Retention and detention ponds shall be designed and constructed in accordance with the criteria of the Soil Conservation Service and shall include the following items:

(a) Velocity-dissipation devices shall be placed at the outfall of all detention or retention structures and along the length of any outfall channel as necessary to provide a nonerosive velocity of flow from the structure to a watercourse.

(b) The developer shall submit to the Town of Chestertown an analysis of the impacts of stormwater flows downstream in the watershed. The analysis shall include hydrologic and hydraulic calculations necessary to determine the impact of hydrograph timing modifications of the proposed development upon a dam, highway, structure or natural point of restricted streamflow, established with the concurrence of the Town of Chestertown, downstream of a tributary of the following size:

[1] The first downstream tributary whose drainage area equals or exceeds the contributing area to the pond; or

[2] The first downstream tributary whose peak discharge exceeds the largest designed release rate of the pond.

(c) The designed release rate of the structure shall be modified if any increase in flooding or stream channel erosion would result at the downstream dam, highway, structure or natural point of restricted streamflow. The release rate of the structure shall:

[1] Be reduced to a level that will prevent any increase in flooding or stream channel erosion at the downstream control point.

[2] Be not less than a one-year predevelopment peak discharge rate.

[3] Meet the requirements established in Subsection A of this section.

(d) Small pond approval shall be obtained from the Soil Conservation District or the Water Resources Administration pursuant to the Natural Resources Article, ~ 8-803(b), of the Annotated Code of Maryland.

(3) Off-site structures to be considered:

(a) Shall have a contributory drainage area not in excess of four hundred (400) acres unless, on a case-by-case basis, a larger drainage area is approved by the Water Resources Administration.

(b) Shall provide for a permanent pool of water or provide for a twenty-four-hour detention period for the one-year-frequency storm peak discharge,

(d) May not be located so as to discharge to Class III natural trout waters identified in COMAR 10.50.01.02I, unless authorized by the Water Resources Administration in permits issued pursuant to the Natural Resources Article, ~ 8-803, of the Annotated Code of Maryland.

(4) The predevelopment peak discharge rate shall be computed assuming that all land uses in the site to be developed are in good hydrologic condition.

(5) The developer shall give consideration to incorporating the use of the natural topography and land cover, such as wetlands, ponds, natural swales and depressions, as they existed prior to development to the degree that they can accommodate the additional flow of water.

(6) The Town of Chestertown shall give preference to the use of swales in place of the traditional use of curbs and gutters, based on a case-by-case review of stormwater management plans.

(7) Where a stormwater management plan involves direction of some or all runoff of the site, it shall be the responsibility of the developer to obtain from adjacent property owners any easements or other necessary property interests concerning flowage of water. Approval of a stormwater management plan does not create or effect any such rights.

(8) The basic design criteria, methodologies and construction specifications, subject to the approval of the Town of Chestertown and the Water Resources Administration, shall be those of the Soil Conservation Service generally found in the most current edition of the following publications or subsequent revisions:

(a) Urban Hydrology for Small Watersheds, Technical Release No. 55, January 1975.

(b) Storm Water Management Pond Design Manual, Maryland Association of Soil Conservation Districts, June 1975.

(d) Soil Conservation Service Standard and Specification for Ponds, Specification No. 378, July 1981.

~ 142-7. Performance bond.

The Town of Chestertown shall require from the developer a surety or cash bond, irrevocable letter of credit or some other means of security acceptable to the Town of Chestertown prior to the issuance of any building and/or grading permit for construction of a development requiring a stormwater management facility. The amount of the security shall not be less than the total estimated construction cost of the stormwater management facility. The bond so required in this section shall include provisions relative to forfeiture for the failure to complete work specified in the approved stormwater management plan, compliance with all the provisions of this chapter and other applicable laws and regulations and any time limitations. The bond shall not be fully released without a final inspection of completed work by the Town of Chestertown, the submission of as-built plans and a certification of completion by the Town of Chestertown of the stormwater management facility as being in compliance with the approved plan and the provisions of this chapter. A provision may be made for partial release of the amount of the bond prorated upon completion and acceptance of the various stages of development as specifically delineated, described and scheduled on the required plans and specifications. The developer shall notify the Town of Chestertown upon completion of each stage that is ready for inspection.

~ 142-8. Inspections.

A. Schedule and reports.

(1) Prior to approval of a stormwater management plan, the developer will submit to the Town of Chestertown a proposed inspection and construction control schedule. The Town of Chestertown or its authorized representative shall conduct inspections and file reports for periodic inspections necessary, during construction of stormwater management systems, to ensure compliance with the approved plans.

(2) No work shall proceed until the Town of Chestertown inspects and approves the work previously completed and furnishes the developer with the results of the inspection reports as soon as possible after completion of each required inspection.

(3) Any portion of the work which does not comply will be promptly corrected by the developer after written notice from the Town of Chestertown. The notice shall set forth the nature of corrections required and the time within which corrections will be made.

(4) The developer shall notify the Town of Chestertown before commencing any work in conjunction with the stormwater management plan and upon completion of the project when a final inspection will be conducted.

B. Inspections required at certain stages of construction. After commencing initial site operations, regular inspections shall be made at the following specified stages of construction:

(1) Infiltration systems. Infiltration systems shall be inspected at commencement, during and upon completion of construction.

(2) Porous paving infiltration systems. Porous paving infiltration systems shall be inspected at the following stages so as to ensure proper placement and allow for infiltration into the subgrade:

(a) Upon completion of stripping, stockpiling and the construction of temporary sediment control and drainage facilities.

(b) Upon completion of the subgrade section.

(d) Upon completion of the top crushed stone course.

(e) Throughout the placement of the porous asphaltic concrete surface course to ensure proper laying temperatures and compaction.

(3) Flow attenuation devices. Flow attenuation devices, such as open vegetated swales, shall be inspected upon completion of construction.

(4) Retention and detention structures. Retention and detention structures shall be inspected at the following stages:

(a) Upon completion of excavation to the subfoundation and, where required, installation of structural supports or reinforcement for structures, including, but not limited to, the following:

[1] Core trenches for structural embankments.

[2] Inlet-outlet structures, antiseep structures and watertight connectors on pipes.

[3] Trenches for enclosed storm drainage facilities.

(b) During placement of structural fill and concrete and installation of piping and catch basins.

(d) During embankment construction.

(e) Upon completion of final grading and establishment of permanent stabilization.

C. Final inspection reports. A final inspection shall be conducted by the Town of Chestertown upon the completion of the stormwater management facility to determine if the completed work is constructed in accordance with the approved plan and this chapter. As-built certification by a registered professional engineer licensed in Maryland is also required to certify that the facility has been constructed as shown on the as-built plans and meets approved plans and specifications. The developer will receive written notification of the results of the final inspection. The Town of Chestertown shall maintain a permanent file of inspection reports.

D. Preventive maintenance inspections.

(1) Preventive maintenance shall be ensured through inspection of all infiltration systems and retention or detention structures by the Town of Chestertown. The Inspection shall occur during the first year of operation and at least every three (3) years thereafter.

(2) Inspection reports shall be maintained by the Town of Chestertown on all retention and detention structures and shall include the following:

(a) The date of inspection.

(b) The name of the inspector.

[1] Vegetation.

[2] Fences.

[3] Spillways.

[4] Embankments.

[5] Reservoir area.

[6] Outlet channels.

[7] Underground drainage.

[8] Sediment load.

[9] Any other item that could affect the proper functioning of the stormwater management system.

(d) Description of needed maintenance.

(3) If after an inspection by the Town of Chestertown the condition of a stormwater management facility presents an immediate danger to the public health or safety because of unsafe conditions or improper maintenance, the Town of Chestertown shall take such action as may be necessary to protect the public and make the facility safe. Any cost incurred by the county/municipality shall be assessed against the owner(s) as provided in ~ 142-9A(3) of this chapter.

~ 142-9. Maintenance of facilities.

A. Inspection and maintenance agreement.

(1) Prior to the issuance of any building permit for which stormwater management is required, the Town of Chestertown shall require the applicant or owner to execute an inspection and maintenance agreement which is binding on all subsequent owners of land served by the private stormwater management facility. Such agreement shall provide for access to the facility at reasonable times for regular inspections by the Town of Chestertown or its authorized representative and for regular or special assessments of property owners to ensure that the facility is maintained in proper working condition to enable it to meet design standards and any provisions established.

(2) The agreement shall be recorded by the applicant and/or owner in the land records of the county/municipality.

(3) The agreement shall also provide that if, after notice by the Town of Chestertown to correct a violation requiring maintenance work, satisfactory corrections are not made by the owner(s) within a reasonable period of time [thirty (30) days maximum], the Town of Chestertown may perform all necessary work to place the facility in proper working condition. The owner(s) of the facility shall be assessed the cost of the work and any penalties, and there shall be a lien on the property which may be placed on the tax bill and collected as ordinary taxes by the county/municipality.

B. Responsibility for maintenance; maintenance schedule.

(1) The owner or any other person or agent in control of the property on which work has been done pursuant to this chapter for private stormwater management facilities shall maintain in good condition and promptly repair and restore all grade surfaces, walls, drains, dams and structures, vegetation, erosion and sediment control measures and other protective devices. Such repairs or restorations and maintenance shall be in accordance with approved plans.

(2) A maintenance schedule shall be developed for the life of any stormwater management facility and shall state the maintenance to be completed, the time period for completion and who shall perform the maintenance. This maintenance schedule shall be printed on the stormwater management plan.

~ 142-10. Appeals.

Any person aggrieved by the action of any official charged with the enforcement of this chapter as the result of the disapproval of a properly filed application for a permit, issuance of a written notice of violation or an alleged failure to properly enforce this chapter in regard to a specific application shall have the right to appeal the action to the Chestertown Board of Appeals. The appeal shall be filed, in writing, within thirty (30) days of the date of official transmittal of the final decision or determination to the applicant, shall state clearly the grounds on which the appeal is based and shall be processed in the manner prescribed for hearing administrative appeals under the Chestertown Zoning Ordinance.

~ 142-11. Violations and penalties.

Any person convicted of violating the provisions of this chapter shall be guilty of a misdemeanor and, upon conviction thereof, shall be subject to a fine of not more than five thousand dollars ($5,000.) or to imprisonment not exceeding one (1) year, or both, for each and every violation, with costs imposed in the discretion of the court. Each day that the violation continues shall be a separate offense. In addition thereto, the Town of Chestertown may institute injunctive, mandamus or other appropriate actions or proceedings for the enforcement of this chapter or to correct violations of this chapter, and any court of competent jurisdiction shall have the right to issue restraining orders, temporary or permanent, injunctions or mandamus or other appropriate forms of remedy or relief.

This HTML document was created 12/17/96 2:47 PM.

Editor's Note: See Ch. 170, Zoning.