CHARACTERISTICS OF HYDRO-GEOCHEMICTRY AND ITS ZONING IN HAI DUONG URBAN AREA

Abstract

Hai Duong urban area consists of Hai Duong city and its vicinity, covering an area of ​​about 500 km2, located in the center of the Red River Delta with three main aquifers: qh, qp and n. The (qp) and (n) aquifers have significant amount of water potential, meaning that they can be sources for public water supply, but poor water quality that can limit the meaning of water supply. Highlights of water quality are:high level of total dissolved solid, iron content, manganese and nitrogen compounds. In all three aquifers water is saline in most of the area, accounting for 22% to 64% of the area. The risk of salinity intrusion can be happened in all aquifers. For the (qp) aquifer, forecast to 2030, under current water exploitation conditions, salinity intrusion rates may range from 2.7 to 9.3 m per year. In the study area, there are three types of hydro-geochemistry: Type I - All layers of water in the section are fresh; Type II - Top (qh) is fresh, (qp) and (n) aquifers are salinity, in which the (qp)is more salty than the (n) layer and the V-type is saline water in (qh) and (qp) aquifers, in the (n) aquifer water is fresh. The I type is normal of hydro-geochemistry; The V type is inverseof hydro-geochemistry due to (n) aquifer which its recharge is far from. In the II type there are both normal and invers of hydro-geochemistry due.