N.J. Admin. Code § 7:9A-5.7

Current through Register Vol. 56, No. 21, November 4, 2024

Section 7:9A-5.7 - Hydraulically restrictive horizons and substrata

(a) Criteria for recognition of hydraulically restrictive horizons and substrata shall include but not be limited to the following:

1. Any soil horizon or substratum which exists immediately below a perched zone of saturation shall be considered hydraulically restrictive. The perched zone of saturation may be observed directly, inferred based on observation of soil profile morphology as prescribed in 7:9A-5.8, or confirmed by testing as prescribed in 7:9A-5.9.

2. Any soil horizon or substratum possessing a clay, silty clay, or silty clay loam texture, as defined in the U.S.D.A. system of classification, shall be considered to be hydraulically restrictive.

3. Any soil horizon or substratum shall be considered hydraulically restrictive if it possesses a sandy clay, clay loam, silt loam or silt texture together with:

i. A massive or platy structure; or

ii. A hard, very hard, firm, very firm or extremely firm consistence.

4. Any cemented horizon or substratum such as ironstone, which remains hard even when soaked in water, shall be considered hydraulically restrictive.

(b) When doubt exists as to whether a soil horizon or substratum should be considered hydraulically restrictive, the administrative authority may require that the soil horizon or substratum in question be tested by an appropriate method, as prescribed in N.J.A.C. 7:9A-6. The soil horizon or substratum shall be considered to be hydraulically restrictive if the measured permeability is slower than 0.2 inch per hour or the percolation rate is slower than 60 minutes per inch.

N.J. Admin. Code § 7:9A-5.7