Impacts of housing development on nutrients flow along canals in a peri-urban area of Bangkok, Thailand

摘要

Change of nutrients load and flow according to land-use change induced by housing developmentnwas investigated in Bang Yai, Nonthaburi, Thailand, which located in the peri-urban areanof Bangkok. Each house in the newly developed residential community was regulatednto be equipped with a septic tank to collect night soil. However, greywater and leachate fromnthe septic tank was collected by a community sewage system and discharged into the canalsnwith insufficient treatment, while the canals still function as infrastructure for irrigationnand transportation. In the study area, built-up area became 1.4 times and agricultural fieldsndecreased by 13% from 2003 until 2007. Total nutrients load to the canals was increased by 25%nas nitrogen and 14% as phosphorus according to the increase of built-up area. Net nutrients loadnfrom agricultural fields was largely set off when we evaluated nutrients inflow from the canalsnto the agricultural field through irrigation. Consequently, nutrients load from domesticnwastewater accounted most of net nutrients load into the canal.