Section 236.126. Surface geology and hydrology

(a) Disqualifying criteria. Potentially suitable sites may not be located:

(1) Within the limits of the 100-year floodplain of a waterway as defined in the Flood Plain Management Act (32 P. S. § § 679.101—679.601).

(2) Within the limits of a coastal floodplain as defined in Federal Executive Order 11988, Flood Plain Management Guidelines (42 U.S.C.A. § 4321, note).

(3) Within the area below a dam which may be threatened with loss of life or serious damage to property if a failure of the dam occurs.

(4) Where erosional processes or mass movement of landforms, such as mass wasting and landslides, would affect the long term stability and isolation of waste.

(5) Where there are slopes greater than 15% on areas of the disposal site where disposal units may be located, as mapped on USGS 7.5-minute quadrangles utilizing a scale of 1:24,000 with a contour interval of either 10 feet or 20 feet or on county topographic maps that utilize a scale of 1:50,000 and a contour interval of 20 feet.

(b) Evaluation requirements. Potentially suitable sites shall be evaluated:

(1) With respect to regional and local geomorphology. Evaluations shall discuss geomorphic features pertinent to site stability and the relationships between regional and local geomorphic features.

(2) With respect to local and site-specific surface hydrology. Characteristics to be evaluated include:

(i) Site drainage conditions.

(ii) Rates of evapotranspiration and infiltration.

(iii) Rates and directions of runoff.

(iv) Fluvial features.

(v) Historical flow conditions.

(vi) Chemical and physical properties of the waters.

(3) To determine the potential for, and the impacts from, major modifications of upstream drainage by others.

(4) With respect to local and site specific erosional processes. Characteristics such as rates, types and directions of erosion shall be described. The potential for mass movement of landforms, including landslides, slumping and mass wasting, shall also be evaluated.

(5) To determine the probable existence and extent of surface water features, including wetlands, springs and ponds that are sustained by groundwater. This evaluation shall also address the potential for future ponding and surface water discharges.

(6) To determine the magnitude, frequency and duration of storm events that would cause inundating floods and probable maximum flood conditions.

Notation

Cross References

This section cited in 25 Pa. Code § 236.101 (relating to scope and applicability); 25 Pa. Code § 236.104 (relating to siting process); 25 Pa. Code § 236.108 (relating to site justification); and 25 Pa. Code § 236.121 (relating to general requirements).