The diversity index is another effective tool to monitor water quality. The results of H index show the
relation between water quality index, land use, community and human activities. The area of upstream
water (before Ayuthaya Island) show the high H index compare with area around Ayuthaya Island. Even
though, BOD, DO and SS could not reveal significant correlated results of H index, it could assume that
human activities and land use might be other main issues affect diversity of mollusks.