Township of Lower Merion, PA General Provisions

Inadequate management of accelerated runoff of stormwater resulting from development throughout the drainage area increases flood flows and rates, contributes to soil erosion and sedimentation of streams, exceeds the capacity of natural and constructed drainage systems, increases cost to the Township to control stormwater, disrupts municipal efforts to manage floodplains and control flooding in the Township and downstream, reduces groundwater recharge, burdens the health of the stream corridor, reduces the number and diversity of aquatic life, contributes to the loss of streamside property and threatens the health, safety and welfare of the public.

A comprehensive program of stormwater management, implemented on a watershed-wide basis, which includes reasonable regulation of development and other activities resulting in increased stormwater flows, is a rational and defensible method of stormwater management and will help protect the public health, safety and welfare of the municipality, their resources and the natural environment.

Stormwater is an important water resource that provides groundwater recharge for water supplies and supports the base flow of streams.

[Added 3-15-2023 by Ord. No. 4262]

(4)

The use of green infrastructure and low-impact development (LID) is intended to address the root cause of water quality impairment by using systems and practices which use or mimic natural processes to 1) infiltrate and recharge, 2) evapotranspirate, and/or 3) harvest and use precipitation near where it falls to earth. Green infrastructure practices and LID contribute to the restoration or maintenance of predevelopment hydrologic conditions.

[Added 3-15-2023 by Ord. No. 4262]

Purpose. This chapter will promote the public health, safety and welfare within the Lower Merion Drainage Area by minimizing the effects of increased stormwater flows from new development. The provisions of this chapter are designed to:

[Amended 7-18-2007 by Ord. No. 3821; 3-15-2023 by Ord. No. 4262]

Meet legal water quality requirements under state law, including regulations at 25 Pa. Code Chapter 93, to protect, maintain, reclaim, and restore the existing and designated uses of the waters of Lower Merion Township.

Preserve natural drainage systems.

Manage stormwater runoff close to the source, reduce runoff volumes and mimic predevelopment hydrologic conditions.

(4)

Provide procedures and performance standards for stormwater planning and management.

(5)

Maintain groundwater recharge to prevent degradation of surface water and groundwater quality and to otherwise protect water resources.

(6)

Prevent scour and erosion of stream banks and streambeds.

(7)

Provide proper operation and maintenance of all stormwater best management practices (BMPs) that are implemented within the municipality.

(8)

Provide standards to meet NPDES permit requirements.

(9)

State regulations require the adoption of ordinances necessary to be compliant with all Act 167 studies performed within the municipality's boundary.

§ 121-2 Compliance required.

[Amended 11-17-1999 by Ord. No. 3546]

Hereafter, no land shall be used, no earth shall be stripped or moved and no structure shall be built or extended without full compliance with the terms of this chapter and other applicable regulations.

Statutory authority. The Township is empowered to regulate these activities by the authority of the Act of October 4, 1978, 32 P.S., P.L. 864 (Act 167), § 680.1 et seq., the Stormwater Management Act, as amended by Act 63 of May 24, 1984, and the Lower Merion Township Code.

Regulatory activities.

The following activities are defined as "regulated activities" and shall be regulated by this chapter, except those that meet the waiver specifications presented thereafter:

(a)

Land development.

(b)

Subdivision.

(c)

Construction of new or additional impervious surfaces.

(d)

Construction of new buildings or additions to existing buildings.

(e)

Diversion or piping of any natural or constructed stream channel.

(f)

Installation of stormwater systems or appurtenances.

(g)

Earthmoving.

[Added 7-18-2007 by Ord. No. 3821]

Any proposed regulated activity, except those defined in § 121-2C(1)(e) and (f), which would create 1,500 square feet or less of additional impervious cover would be exempt from the requirements of this chapter regarding control of the peak rate of flow. The regulated activity may be required to satisfy the standards for groundwater recharge and/or water quality, at the discretion of the Township.

For phased development, the entire development plan is to be used in determining conformance with this criteria. Additional impervious surface shall include, but not be limited to, any roof, parking area, driveway area, street or sidewalk constructed as part of or for the proposed regulated activity. Any areas designed initially as semi-impervious (gravel, crushed stone, porous pavement, etc.) shall be considered impervious for the purpose of waiver requested evaluation. No waiver shall be granted for regulated activities as defined in § 121-2C(1)(e) and (f).

Compatibility with other ordinance requirements. Approvals issued pursuant to this chapter do not relieve the applicant of the responsibility to secure required permits or approvals for activities regulated by any other applicable code, rule, act or ordinance.

§ 121-3 Terms defined; word usage.

[Amended 6-15-1988 by Ord. No. 3098; 11-17-1999 by Ord. No. 3546]

Word usage. For the purposes of this chapter, certain terms and words used herein shall be interpreted as follows:

Words used in the present tense include the future tense. The singular number includes the plural, and the plural number includes the singular. Words of masculine gender include feminine gender and words of feminine gender include masculine gender.

The word "includes" or "including" shall not limit the term to the specific example but is intended to extend its meaning to all other instances of like kind and character.

BEST MANAGEMENT PRACTICE (BMP)

The word "person" includes an individual, firm, association, organization, partnership, trust, company, corporation or any other similar entity.

(4)

The words "shall" and "must" are mandatory. The words "may" and "should" are permissive.

(5)

The words "used" or "occupied" include the words "intended, designed, maintained or arranged to be used or occupied."

(6)

The word "building" includes the word "structure" and shall be construed as if followed by the words "or part thereof."

Definitions. As used in this chapter, the following words shall have the meanings indicated:

ALTERATION

As applied to land, a change in topography as a result of the moving of soil or rock from one location or position to another; also the changing of surface conditions by causing the surface to be more or less impervious; land disturbance.

APPLICANT

A landowner or developer who has filed an application for approval to engage in any regulated activities as defined in § 121-2C of this chapter.

BEDROCK

The solid, undisturbed rock in place either at the ground surface or beneath surficial soil deposits.

Activities, facilities, designs, measures, or procedures used to manage stormwater impacts from regulated activities, to meet state water quality requirements, to promote groundwater recharge, and to otherwise meet the purposes of this chapter. Stormwater BMPs are commonly grouped into one of two broad categories or measures: "structural" or "nonstructural." In this chapter, "nonstructural BMPs or measures" refers to operational and/or behavior-related practices that attempt to minimize the contact of pollutants with stormwater runoff, whereas structural BMPs or measures are those that consist of a physical device or practice that is installed to capture and treat stormwater runoff. Structural BMPs include, but are not limited to, a wide variety of practices and devices, from large-scale retention ponds and constructed wetlands to small-scale underground treatment systems, infiltration facilities, filter strips, low-impact design, bioretention, wet ponds, permeable paving, grassed swales, riparian or forested buffers, sand filters, detention basins, and manufactured devices. Structural stormwater BMPs are permanent appurtenances to the project site.

[Amended 3-15-2023 by Ord. No. 4262]

BORROW PIT

An open pit from which soil is excavated as a single incident for use at a single construction site.

CISTERN

An underground reservoir or tank for storing stormwater.

CONSERVATION DISTRICT

The Montgomery County Conservation District (MCCD).

CONVEYANCE

A natural or man-made, existing, or proposed stormwater management facility, feature or channel used for the transportation or transmission of stormwater from one place to another. For the purposes of this chapter, "conveyance" shall include pipes, drainage ditches, channels, and swales (vegetated or other), gutters, stream channels, and like facilities or features.

[Added 3-15-2023 by Ord. No. 4262]

CULVERT

A structure with appurtenant works which carries a stream or concentrated flow under or through an embankment or fill.

DAM

An artificial barrier, including the appurtenant works, constructed for the purpose of impounding or storing water or any other fluid or semifluid, or any other bank, fill or structure for highway, railroad or other purposes which does or may impound water or any other fluid or semifluid.

DEP

The Pennsylvania Department of Environmental Protection.

DESIGNEE (DESIGNATED REPRESENTATIVE)

Any person or consultant designated by the Township to administer, review or enforce the provisions of this chapter whether by contract or by memorandum of understanding.

DESIGN STORM

The magnitude and temporal distribution of precipitation from a storm event measured in probability of occurrence and duration (a twenty-five-year, twenty-four-hour storm, for example), used in the design and evaluation of stormwater management systems.

DETENTION BASIN

An impoundment structure designed to manage stormwater runoff by temporarily storing the runoff and releasing it at a predetermined rate.

DEVELOPER

A person, partnership, association, corporation or other entity, or any responsible person therein or agent thereof, that undertakes any regulated activity of this chapter.

DEVELOPMENT

Any subdivision or land development. The improvement of one lot or two or more contiguous lots, tracts or parcels of land for any purpose or any alteration of land not for agricultural or conservation purposes, which includes earthmoving, filling or stripping on a tract. Development includes, but is not limited to, road construction; utility installation; public, commercial or industrial facility construction; and mining and quarrying, and also includes water resource management.

DEVELOPMENT SITE

The specific tract of land for which the regulated activity is proposed.

DRAINAGE EASEMENT

A right granted by a landowner to a grantee, allowing the use of private land for stormwater management purposes.

DRAINAGE PLAN

The documentation of the proposed storm management system to be used for a given development site, the contents of which are established in § 121-4H(2).

EARTHMOVING

Any act by which soil or bedrock is cut into, quarried, displaced or relocated.

EROSION

The physical removal of soil and bedrock by the action of wind, water, ice or other natural forces.

EVAPOTRANSPIRATION

The combined processes of evaporation from the water or soil surface and transpiration of water by plants.

[Added 3-15-2023 by Ord. No. 4262]

EXISTING GRADE

The vertical elevation of the ground surface prior to earthmoving or filling.

FILL

Any act by which earth, sand, gravel, rock or any other material is deposited, placed, pushed, dumped, pulled, transported or moved to a new location, and shall include the conditions resulting therefrom.

FINISHED GRADE

The final vertical elevation of the ground after development.

FLOODPLAIN

Any land area susceptible to inundation by water from any natural source or delineated by applicable Department of Housing and Urban Development, Federal Insurance Administration Flood Hazard Boundary Maps as being a special flood hazard area. Also included are areas that comprise Group 13 Soils, as listed in Appendix A of the DEP Technical Manual for Sewage Enforcement Officers (as amended or replaced from time to time by DEP).[1]

FREEBOARD

The incremental depth in a stormwater management structure provided as a safety factor of design, above that required to convey the design runoff event.

GREEN INFRASTRUCTURE

Systems and practices that use or mimic natural processes to infiltrate, evapotranspirate or reuse stormwater on the side where it is generated.

[Added 3-15-2023 by Ord. No. 4262]

GROUNDWATER RECHARGE

Any area from which water penetrates and subsequently passes into the groundwater supply.

IMPERVIOUS SURFACE

A surface that prevents the infiltration of water into the ground. Impervious surfaces shall include, but are not limited to, roofs, additional indoor living spaces, patios, garages, storage sheds and similar structures; and any new streets or sidewalks.

[Amended 2-26-2020 by Ord. No. 4184; 3-15-2023 by Ord. No. 4262]

INFILTRATION STRUCTURE

A structure designed to infiltrate stormwater in whole or in part (for example, a French drain, infiltration basin, seepage pit or seepage trench).

LAND DEVELOPMENT

Any of the following activities:

The improvement of a lot, or two or more contiguous lots, tracts or parcels of land for any purpose involving:

(a)

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.

(b)

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, condominiums, building groups or other features.

A subdivision of land.