The aquifer (group) is 0~99.05m thick with an average thickness of 57.65m, of which the sand and gravel layer is 0~85.80m thick with an average thickness of 37.93m m. The lower strata directly cover the coal measure strata, from southeast to northwest, distributed along the low concave surface of the bedrock, extending and thinning to the north and south sides, and pinching out at the ancient topographic uplift. Lithology is mainly composed of muddy gravel layer, followed by fine silty sand. Gravel is quartzite, Shi Ying sandstone and magmatic rock. Limestone gravel is occasionally found. Gravel diameter is about 5~20mm, with loose structure.