"Restrictive layer" means a soil horizon that restricts the downward flow of water and is uncharacteristic of the soil layers above and below, such as a layer of soil with a consistence of firm or very firm, cemented horizons, or stratified layers of silt, loam or clay within the soil profile.
N.H. Admin. Code § Env-Wq 1002.60
(See Revision Note at chapter heading for Env-Wq 1000) #9086, eff 2-9-08; renumbered by #9904-A (from Env-Wq 1002.59)