[HISTORY: Adopted by the City Council of the City of Lower Burrell 5-11-1992 by Ord. No. 6-1992. Amendments noted where applicable.]
This chapter is adopted and implemented to achieve the following general purposes and objectives:
To manage stormwater runoff resulting from land alteration and disturbance activities in accordance with the watershed stormwater management plans adopted by Westmoreland County as required by the Pennsylvania Stormwater Management Act (Act 167 of 1978, as amended).
Editor's Note: See 32 P.S. § 680.1 et seq.
To utilize and preserve desirable existing natural drainage systems and to preserve the flood-carrying capacity of streams.
To encourage natural infiltration of rainfall to preserve groundwater structures in the City.
The provisions of this chapter shall apply to all developments, improvements, subdivisions, land developments and environmental disturbances unless specifically exempted or otherwise modified herein.
For the purpose of this chapter, these terms shall be defined as follows:
- The Stormwater Management Act (Act of October 4, 1978, P.L. 864, No. 167, as amended by Act of May 24, 1984, No. 63, 32 P.S. §§ 680.1–680.17).
- A landowner or developer, as defined by this chapter, who has filed an application for a land development or for a development, including his/her heirs, successors and assigns.
- A natural stream that conveys water; a ditch or open channel excavated for the flow of water.
- Points where watercourses join together.
- CONSERVATION DISTRICT (WCCD)
- The Westmoreland County Conservation District.
- The County of Westmoreland, Pennsylvania.
- A pipe, conduit or similar structure including appurtenant works which carries a stream under or through an embankment or fill.
- Any artificial barrier, together with its appurtenant works, constructed for the purpose of impounding or storing water or a structure for highway, railroad or other purposes which may impound water.
- DESIGN STORM
- The magnitude of precipitation from a storm event measured in probability of frequency of occurrence (e.g., fifty-year storm) and duration (e.g., 24 hours), and used in computing stormwater management control systems.
- The slowing, dampening or attenuating of runoff flow entering the natural drainage pattern or storm drainage system by temporarily holding water on a surface area such as detention basins, reservoirs, on roof tops, in streets, parking lots, or within the drainage system itself, and releasing the water at a desired rate of discharge.
- DETENTION BASIN (STORAGE FACILITY)
- A basin designed to retard stormwater runoff by temporarily storing the runoff and releasing it at a predetermined rate. A detention basin can be designed to drain completely after a storm event, or it can be designed to contain a permanent pool of water.
- Any landowner, agent of such landowner or tenant with the permission of such landowner, who makes or causes to be made a subdivision, land development or development.
- Any activity, construction, alteration, change in land use or similar action that effects stormwater runoff characteristics.
- DEVELOPMENT SITE
- A lot, parcel or tract of land on which development is taking place or is proposed.
- Rate of flow, specifically fluid flow. A volume of fluid flowing from a conduit or channel, or being released from detention storage, per unit of time. Commonly expressed as cubic feet per second (cfs), million gallons per day (mgd), gallons per minute (gpm) or cubic meters per second (cms).
- DISCHARGE CONTROL POINT
- A point of hydraulic concern, such as bridge, culvert or channel section, for which the rate of runoff is computed.
- Interception and removal of excess surface water or groundwater from land by artificial or natural means.
- DRAINAGE AREA
- The contributing area to a single drainage basin, expressed in acres, square miles or other units or area; also called a catchment area, or river basin; the area served by a drainage system or by a watercourse receiving storm and surface water.
- DRAINAGE EASEMENT
- A nonpossessive right or interest allowing the use of private and for stormwater management purposes.
- Any structure or activity which in any manner changes, expands or diminishes the course, current or cross-section of any watercourse, floodway or body of water.
- ENGINEER (CITY ENGINEER)
- A professional engineer duly appointed as the engineer for the City of Lower Burrell.
- The wearing away of the land surface by running water, wind, ice or other geological agents, including such process as gravitational creep.
- EXCAVATION (CUT)
- Any act by which soil or rock is cut into, dug, quarried, uncovered, removed, displaced or relocated and shall include the conditions resulting therefrom.
- A normally dry land area adjacent to stream channels that is susceptible to being inundated by overbank stream flows. For regulatory purposes, the Floodplain Management Act (Act of October 4, 1978, P.L. 851, No. 166) and regulations pursuant to the Act define the floodplain as the area inundated by a one-hundred-year flood and delineated on a map prepared by the Federal Emergency Management Agency (FEMA). See Chapter 170, Floodplain Management.
- The branch of engineering concerned with the mechanics of fluids, especially liquids. As applied in stormwater management, the study of the characteristics of water flow in, and conveyance capacity of, a watercourse, considering such factors as depth, velocity and turbulence.
- The science dealing with the waters of the earth and their distribution and circulation through the atmosphere. Engineering hydrology deals with the application or hydraulic concepts to the design of projects for use and control of water.
- A graph showing, for a given point on a stream or for a given point in any drainage system, the discharge, stage, velocity or other property of water in respect to time.
- IMPERVIOUS MATERIAL OR SURFACE
- Material which resists the entrance or passing through of water or other liquids.
- LAND DEVELOPMENT
- As defined by the Municipalities Planning Code [§ 107(a)]:
- A. The improvement of one lot or two or more contiguous lots, tracts or parcels of land for any purpose involving:
- (1) A group of two or more residential or nonresidential buildings, whether proposed initially or cumulatively or a single nonresidential building on a lot or lots regardless of the number of occupants or tenure; or
- (2) The division or allocation of land or space, whether initially or cumulatively, between or among two or more existing or prospective occupants by means of, or for the purpose of, streets, common areas, leaseholds, and condominiums, buildings groups, or other features.
- B. A subdivision of land.
- C. Development in accordance with § 503(1.1) of the Municipalities Planning Code.
- LAND DISTURBANCE
- Any activity involving grading, tilling, digging or filling or stripping of vegetation; or any other activity which causes land to be exposed to the danger of erosion.
- The City of Lower Burrell, Westmoreland County, Pennsylvania.
- Natural Resources Conservation Service, U.S. Department of Agriculture.
- Any structure or assembly of materials, including fill, above or below the surface of land or water; and activity which might impede, retard or change flood flows; an encroachment.
- Points or areas at which stormwater runoff leaves a site, which may include streams, storm sewers, swales or other well defined natural or artificial drainage features, as well as areas of dispersed overland flows.
- OUTLET STRUCTURE
- A structure designed to control volume of stormwater runoff that passes through it during a specific length of time.
- Pennsylvania Department of Environmental Protection.
- PEAK RATE OF RUNOFF OR DISCHARGE
- The maximum rate of flow water at a given point and time resulting from a predetermined storm.
- PERFORMANCE STANDARD
- A standard which establishes an end result or outcome which is to be achieved but does not prescribe specific means for achieving it. The "release rate percentage" is an example of a performance standard.
- PRECIOUS MATERIAL
- Material which permits the passage or entrance of water or other liquid.
- POINT OF INTEREST
- A point of hydrological and hydraulic importance used for computing a release rate percentage. These may include points of stream confluences, an existing obstruction or problem area or other similar points.
- RATE OF RUNOFF
- Instantaneous measurement of water flow expressed in a unit of volume per unit of time, also referred to as "discharge." Usually stated in cubic feet per second (cfs) or gallons per minute (gpm).
- REGISTERED PROFESSIONAL ENGINEER
- An engineer licensed in the Commonwealth of Pennsylvania.
- Solid material, both mineral and organic, that is in suspension, is being transported, or has been moved from its site of origin by air, water, gravity or ice and has come to rest on the earth's surface.
- The process by which mineral or organic matter is accumulated or deposited by moving wind, water, or gravity.
- SEDIMENT BASIN
- A barrier or dam built at a suitable location to retain rock, sand, gravel, silt or other material.
- SMALL DEVELOPMENT
- Any subdivision, development or land development which results, or will result when fully constructed, in the creation of 3,000 square feet, or less, of impervious surface area.
- SOIL-COVER COMPLEX METHOD
- A method of runoff computation developed by the U.S. Natural Resources Conservation Service and found in its publication "Urban Hydrology for Small Watersheds," Technical Release No. 55, NRCS, January 1975 (or most current edition).
- SPECIFICATION STANDARD
- A standard which prescribes the exact characteristics to be used, leaving little choice to the applicant. The design standards for storm sewers are specification standards.
- STORAGE FACILITY
- See "detention basin."
- STORM SEWER
- A sewer that carries intercepted surface runoff, street water and other washwater, or drainage, but excludes domestic sewage and industrial wastes.
- STORM SEWER DISCHARGE
- Flow from a storm sewer that is discharged into a receiving stream.
- STORMWATER COLLECTION SYSTEM
- Natural or engineered structures which collect and transport stormwater through or from a drainage area to the point of final outlet including, but not limited to, any of the following: conduits and a pertinent features, canals, channels, ditches, streams, culverts, streets, retention structures and pumping stations.
- STORMWATER RUNOFF
- Waters resulting from snow melt or precipitation within a drainage basin, flowing over the surface of the ground, collected in channels and conduits, and carried by receiving streams.
- A watercourse.
- A low-lying stretch of land which gathers or carries surface water runoff.
- TIME OF CONCENTRATION
- The time period necessary for surface runoff to reach the outlet of a subarea from the hydraulically most remote point in the tributary drainage area.
- VOLUME OF STORMWATER RUNOFF
- Quantity of water normally measured in cubic feet or acre-feet, measured or determined analytically from: runoff coefficients; rainfall/runoff ratios; and areas underneath hydrographs.
- WATERCOURSE (WATERWAYS)
- Any channel of conveyance of surface water having a defined bed and banks, whether natural or artificial with perennial or intermittent flow.
Editor's Note: See 32 P.S. § 680.1 et seq.
Editor's Note: See 53 P.S. § 10107(a).
Editor's Note: See 53 P.S. § 10503(1.1).
General requirements. No final subdivision or land development plan shall be approved, no permit authorizing construction issued, or any earthmoving or land disturbance activity initiated until the final stormwater management plan for the development site is approved in accordance with the provisions of this chapter. This requirement shall not apply to municipal sewer, water, gas, electric or public utility company excavations for the maintenance, repair or installation of service lines or rights-of-way.
Exemption for small developments.
At the time of application, the City shall determine if the development, environmental disturbance, subdivision or land development qualifies as a "small development" and, therefore, is eligible for a simplified stormwater plan submission.
A small development shall be exempt from the preparation of a stormwater management plan as specified by Subsection B(3) or (4) of this section. However, such developments shall provide safe management of stormwater runoff in accordance with the performance standard of § 252-8 and as approved by the City Engineer.
Applications for small developments shall include a plan which describes, narratively and graphically, the type and location of proposed on-site stormwater management techniques or the proposed connection to an existing storm sewer system. The plan should show accurately site boundaries, two-foot interval contours and any watercourses, floodplains or existing drainage facilities or structures located on the site. The plan must be prepared by a registered professional engineer.
The City Engineer shall review and approve the proposed provisions for stormwater management for a small development. Where the applicant is proposing to connect to an existing storm sewer, the developer's engineer shall determine that sufficient capacity exists in the storm sewer from the point of connection to the point of outlet in the natural drainage system. The engineer shall also determine if the proposed development site is part of a larger parcel or tract for which a stormwater management plan was approved previously and, therefore, subject to any specific stormwater management control contained in the prior plan.
For a parcel or tract of land under single ownership, only one application for a small development, as defined above, shall be permitted before requiring a stormwater management plan for the entire parcel.
Stormwater plan contents; preliminary subdivision/development/land development plan submission.
General format. The stormwater plan shall contain the following information:
Floodplain boundaries. Identify one-hundred-year floodplains on the development site (as appropriate) based on the flood insurance study maps.
Natural features. Show all bodies of water (natural and artificial), watercourses (permanent and intermittent), swales, wetlands and other natural drainage courses on the development site, or which will be affected by runoff from the development.
Soils. Provide an overlay showing soils types and boundaries within development site (consult county, NRCS, and U.S. Geologic Survey for information).
Contours. Show existing and final contours at intervals of two feet. In areas with slopes greater than 15%, five-foot contour intervals may be used.
Stormwater management controls. Show any and all existing stormwater management or drainage controls and/or structures, such as sanitary and storm sewers, swales, culverts, etc., which are located on the development site, or which are located off-site but will be affected by runoff from the development.
Professional certification. The stormwater management plan (including all calculations) must be prepared and sealed by a registered professional engineer with training and expertise in hydrology and hydraulics. Documentation of qualifications may be required by the City.
Runoff calculations. Calculations for determining pre- and post-development discharge rates and for designing proposed stormwater control facilities must be submitted with the stormwater management plan. All calculations shall be prepared using the method and data prescribed by § 252-8.
Stormwater controls. All proposed stormwater runoff control measures must be shown on the plan, including methods for collecting, conveying and storing stormwater runoff on-site, which are to be used both during and after construction.
If the development is to be constructed in stages, the applicant must demonstrate that stormwater facilities will be installed to manage stormwater runoff safely during each stage of development.
Easements; rights-of-way; deed restrictions. All existing and proposed easements and rights-of-way for drainage and/or access to stormwater control facilities shall be shown and the proposed owner identified. Any areas subject to special deed restrictions relative to or affecting stormwater management on the development site must be shown.
Other permits/approvals. A list of any approvals/permits relative to stormwater management that will be required from other governmental agencies (e.g., an obstructions permit from PaDEP) and anticipated dates of submission/receipt should be included with the preliminary plan submission. Copies of applications may be required by the City where they may be helpful for the stormwater plan review.
Maintenance program. The preliminary application shall contain a proposed maintenance plan for all stormwater control facilities, in accordance with the following:
Identify the proposed ownership entity (e.g., City, property owner, a homeowner's association, other management entity).
Include a maintenance program for all facilities, outlining the type of maintenance activities, probable frequencies, personnel and equipment requirements, and estimated annual maintenance costs. Maintenance program shall include specific requirements for "during construction" and for "after construction."
Identify method of financing continuing operation and maintenance if facility is to owned by other than City or other governmental agency.
In addition to the requirements of this subsection, the stormwater plan must satisfy all of the requirements contained in the building and housing codes of the City of Lower Burrell pertaining to drainage systems, which provisions are hereby incorporated herein by reference and Chapter 170, Floodplain Management, and Chapter 154, Erosion and Sedimentation Control Ordinance.
Stormwater plan contents; final subdivision/development/land development plan submission. The final plan submission shall contain the following:
All information pertaining to stormwater management from the preliminary plan along with any changes.
Final plan maps and drawings showing the exact nature and location of all temporary and permanent stormwater management controls along with design and construction specifications.
A schedule for the installation of all temporary and permanent stormwater control measures and devices.
An accurate survey showing all current and proposed easements and rights-of-way and copies of all proposed deed restrictions.
A maintenance program establishing ownership and maintenance responsibilities for all stormwater control facilities (identify specific person or entity) and detailing financial requirements and sources of funding. Applicant shall submit any legal agreements required to implement the maintenance program and copies of the maintenance agreement as specified by § 252-10B.
Financial guarantees to ensure that all stormwater controls will be installed properly and function satisfactorily.
Prior to submitting the preliminary subdivision/development/land development plan, applicants are urged to consult with the City, the Westmoreland County Planning Department and the County Conservation District on the requirements for safely managing stormwater runoff from the development site in a manner consistent with the City ordinances. These agencies may be helpful in providing the data that are necessary for preparing the stormwater management plan.
Applicants are encouraged to submit a sketch plan with a narrative description of the proposed stormwater controls for general guidance and discussion with City and other agencies.
While strongly recommended, the preapplication phase is not mandatory, and any review comments provided by City or other agencies are advisory only and do not constitute any legally binding action on the part of the City of any County agency.
Preliminary and final stormwater plan reviews.
Preliminary and final plans required. Stormwater management plans, in accordance with the requirements of § 252-4D, will be submitted with the preliminary and final subdivision or land development plan application.
Review by City Engineer and Conservation District. Preliminary and final plans will be reviewed by the City Engineer and County Conservation District. At its discretion, the City may also engage other specialties in hydrology or hydraulics to assist with the stormwater plan review.
Notification of affected municipalities. The City shall notify municipalities upstream and downstream of the development of the development site, which may be affected by the stormwater runoff and proposed management system for the site, when both the preliminary and final plan applications are submitted. Copies of the plans will be made available to the municipalities upon request. Comments received from any affected municipality will be considered by the City Engineer and will be submitted with the Engineer's report to the Planning Commission and City Council.
City Engineer's review. The City Engineer shall approve or disapprove the preliminary and final stormwater management plan based on the requirements of the City ordinances, the review by the Westmoreland County Conservation District and good engineering practice. The Engineer shall submit a written report, along with supporting documentation to the City Planning Commission for its consideration as part of the overall subdivision or land development plan review.
Status of Engineer's determination. The approval/disapproval of the site's stormwater management plan by the City Engineer shall be considered final. The Commission or City Council may require modifications or alternate approaches to the stormwater management controls if they feel such approaches are in the best interest of the residents and the results complies with good engineering practices.
Approval of stormwater plan required for subdivision/development/land development approval. No preliminary or final approval shall be granted for the overall subdivision or land development application until a stormwater management plan for the site has been approved.
Permits required from other governmental agencies. Where the subdivision or land development application requires an obstruction or erosion/sedimentation permit from PaDEP, the final subdivision or land development plan approval shall be conditional upon receipt of such permits. However, no building permit shall be issued or construction started until the permits are received and copies filed with the City.
Costs of review by engineer and other specialists appointed by the City. The costs of review of all stormwater plans by the City Engineer and other specialists appointed by the City shall be paid by the applicant.
Filing fees. City Council may set a filing fee for stormwater plans, which may be adjusted from time to time by resolution.
Upon final approval subdivision/development/land development plan approval, the applicant may commence to install or implement the approved stormwater management controls, subject to the provisions of § 252-4D(6) above. If site development or building construction does not begin within two years of the date of final approval of the subdivision of land development plan, then before doing so, the applicant shall resubmit the stormwater management plants to verify that no condition has changed that would affect the feasibility or effectiveness of the previously approved stormwater management controls. Further, if for any reason development activities are suspended for two years or more, then the same requirement for resubmission for the stormwater management plan shall apply.
Procedure for approving plan modifications. Request for modification in the finally approved stormwater management controls shall be submitted to the City Engineer as follows:
If request is initiated before construction begins, the stormwater plan must be resubmitted and reviewed according to the procedures in § 252-5.
If request is initiated after construction is underway, the City Engineer shall have the authority to approve or disapprove the modification, based on field inspection; provided:
Notification of the Engineer's action shall be sent to the Planning Commission and City Council. The City Council may issue a stay of stormwater plan modification within five days and require the permittee to resubmit the plan modification for full stormwater plan review in accordance with the procedures in § 252-5.
The stormwater management plan shall be designed on the following basis:
The maximum post-development release rate shall be limited to the pre-development peak discharge for each design storm return period.
Stormwater management design calculations shall be based on the Rational Method for sites less than five acres or the Natural Resources Conservation Service TR-55 Method for sites greater than three acres. Sites between three acres and five acres may use either method.
The minimum storage capacity will be that volume required by routing the post-development twenty-five-year, twenty-four-hour storm release at a rate not to exceed the pre-development twenty-five-year twenty-four-hour storm. For the Rational Method, storage shall be determined by using the following formula:
(Cpost - Cpre)RA
Storage volume (cubic feet)
Twenty-five-year twenty-four-hour rainfall (feet)
Development area (square feet)
For the NRCS TR-55 Method, storage basin detention capacity shall be calculated as described in the manual "Urban Hydrology for Small Watersheds" or by computer programs using those methods.
The design maximum runoff velocity for all storms less than or equal to the twenty-five-year storm shall be three feet per second.
Stormwater discharges may be retarded by temporary containment devices including, but not limited to, flat rooftops, curbed or depressed parking areas, underground reservoirs and/or holding ponds on the property to be maintained by the property owner. Discharge outlets must provide for complete dewatering of the storage facility.
The developer shall secure, where necessary, any drainage easements off the property to connect the stormwater management system with an existing stream, recognized wet weather stream versus wet weather stress drainage line. All designs submitted must consider and be sized to pass discharges through existing culverts and drainage.
No erosion or sedimentation by water shall be permitted which will carry substances into the waters of the commonwealth, neighboring properties or public rights-of-way. The requirements and standards set forth in Chapter 154, Erosion and Sediment Control, shall act as the erosion and sedimentation controls and are incorporated herein by reference.
The stormwater management plan for the development site must establish responsibilities for the continuing operation and maintenance of all proposed stormwater control facilities. The proposed maintenance plan must be consistent with the general objectives set forth in § 252-4A of this chapter.
City Council shall make the final determination on the continuing maintenance responsibilities as part of the development application review and reserves the right to accept the ownership and operating responsibility of any or all of the stormwater management controls.
Maintenance agreement for privately owned stormwater facilities.
Prior to final approval of the site's stormwater management plan, the property owner shall sign and record a maintenance agreement covering all stormwater control facilities which are to be privately owned. The agreement shall stipulate that:
The owner shall maintain all facilities in accordance with the approved maintenance schedule and shall keep all facilities maintained in a safe and attractive manner.
The owner shall grant to the City the right of access for periodic inspections and any elective maintenance.
The owner shall keep on file with the City the name, address and telephone number of the person or company responsible for maintenance activities; in the event of a change, new information will be submitted to the City within 10 days of the change.
The owner shall establish any special maintenance funds or other financing sources, in accordance with the approved maintenance plan.
The owner shall pay the amount due, if any, to any special stormwater facility maintenance fund hereinafter established.
If the owner fails to maintain the stormwater control facilities, following due notice by the City to correct the problems, the City, without waiving any other remedies, may perform the necessary maintenance or corrective work. The owner shall reimburse the City for all costs, plus 10% to cover overhead.
Other items may be included in the agreement where determined necessary to guarantee the satisfactory maintenance of all facilities. The maintenance agreement shall be subject to the review and approval of the City Solicitor.
The City Engineer or a designated representative shall inspect the construction of the temporary and permanent stormwater management for the development site. The permittee shall notify the Engineer 48 hours in advance of the completion of the following key development phases:
Prior to starting any construction but after all temporary erosion and sedimentation controls have been installed.
At the completion of rough grading, but prior to placing topsoil, permanent drainage or other site development improvements and ground covers.
Completion of any final grading, vegetative control measures, or other site restoration work done in accordance with the approved plan and permit.
No work shall commence on any subsequent phase until the preceding one has been inspected and approved. If there are deficiencies in any phase, the City Engineer shall issue a written description of the required corrections and stipulate the time by which they must be made.
If, during construction, the contractor or permittee identifies any site conditions, such as subsurface soil conditions, alterations in surface or subsurface drainage, which could affect the feasibility of the approved stormwater facilities, he must notify the City Engineer within 24 hours of the discovery of such condition and request a field inspection. The City Engineer shall determine if the condition requires a stormwater plan modification.
In cases where stormwater facilities are to be installed in areas of landslide-prone soils or other special site conditions exist, the City may require special precautions such as soil tests and core borings, full-time resident inspectors and/or similar measures. All costs of any such measures shall be borne by the permittee.