Palmer Township's topography may be defined
as a karst topography due to the presence of carbonate rock that generally
consists of dolomite and limestone. The limestone and dolomite are
divided into formations. The carbonate formations present in Palmer
Township consist of Epler, Rickenbach, Allentown, Jacksonburg and
Leithsville Formations. These formations are susceptible to the development
of solution cavities and sinkhole development. Therefore, anyone considering
developing property within the Township should be aware of the potential
geological hazards. The regulations contained herein are intended
to minimize the risk of sinkhole occurrence in areas of new development
and on lands adjacent to these developments.
The regulations established by this ordinance
shall apply to all land development or subdivision applications pertaining
to commercial, governmental (except those owned by Palmer Township)
and industrial/office structures, apartment complexes and multiple
single-family home developments with three or more lots.
All single-family homes and the alteration of
single-family homes to include detached structures such as garages,
barns and swimming pools shall be exempt from the regulations established
in this article.
As used in this article, the following terms
shall have the meanings indicated:
CARBONATE ROCK
Rock types that are affected by dissolution weathering process
caused by slightly acidic groundwater. The most common types of rock
that are categorized as carbonate rock are limestone (calcium carbonate)
and dolomite (calcium magnesium carbonate).
CAVERN
Interconnected solution features within the bedrock surface.
CLAY LINER
Fine-grained soil that is used in the construction of a liner
that limits the rate of surface water intrusion into the subsurface.
CLOSED DEPRESSION
A bowl-shaped depression in the land surface characterized
by internal drainage. A ghost lake is a closed depression which has
visible standing water after a heavy rainfall event.
FAULT
A fracture in bedrock along which movement has taken place.
FINE GRAINED SOIL
Materials that predominantly consist of silt and clay size
particles.
IMPERMEABLE LINERS
A liner system that prohibits the infiltration of surface
water into the subsurface.
KARST
The terrain that results from the dissolution of carbonate
rock.
KARST PROCESS
The dissolution of carbonate rock by slightly acidic groundwater.
Dissolution weathering, the removal of soluble materials from intact
carbonate rock by slightly acidic groundwater.
LINEAMENTS
Aligned topographic features that locate faults and fractures.
RESIDUAL SOIL
Soils derived from the in-place weathering of the underlying
bedrock.
SINKHOLE
Localized land surface subsidence or collapse due to karst
processes. Sinkholes are categorized as solution sinkholes, collapse
sinkholes and subsidence sinkholes.
SPRING
Where water flows naturally out of the bedrock or the overlying
soil mantle on to the land surface.
In carbonate areas, alteration and development
of land may be hazardous with respect to foundation safety of structures,
the creation of unstable land as a result of changes in drainage,
and the contamination of ground and surface waters. Within the limitations
of the information available at the time of the review of individual
applications, the Township shall attempt to make reasonable judgments
as to the applicant's compliance with the Carbonate Ordinance. Under
no circumstances shall the Township of Palmer or any officer or employee
of the Township or consultant to the Township assume any liability
for any damages that may result from an applicant's or any interested
party's reliance upon the regulations of the Carbonate Ordinance or
any decisions made by the Township in the administration of such regulations
by an applicant, developer, and/or any interested party.