What is the Sediment?

Sediment is the loose sand, clay, silt and other soil particles that settle at the bottom of a body of water. Sediment can come from soil erosion or from the decomposition of plants and animals. Wind, water and ice help carry these particles to rivers, lakes and streams.

Contaminated sediments present risk to human health and the environment and limit the uses of many water bodies. Sediments can become contaminated in a number of ways:

  • Urban runoff that discharges to surface waters often contains oil, grease, heavy metals and other harmful substances.
  • Agricultural runoff may contain nutrients and pesticides.
  • Industrial spills and releases, especially those that occurred before controls were in place, can put damaging products into the water.
  • Airborne contaminants may also be deposited in sediments, such as mercury.
  • Contaminated groundwater can discharge through sediments to the overlying surface water.

Introduction of Taiwan Sediment Quality Information System

Since 2010, the Taiwan Ministry of Environment (MOENV) has incorporated sediment quality management into the "Soil and Groundwater Pollution Remediation Act", and has formulated the supporting legal systems, administrative rules, and guidelines for sediment quality management year by year. Starting from 2014, authorities in charge of water bodies such as rivers, reservoirs, irrigation canals, etc. should regularly analyze the sediment quality at least once every five years, and publicly announce the state of sediment quality.

The Taiwan Sediment Quality Information System has integrated sediment quality analysis data reported over the years and has a perfect function to inquire and display the information. users can learn about what is the sediment, the sediment quality reporting process and investigation methods, sediment quality indicators, limits, analyzing methods, and other related information. The Sediment quality spatial / data query tool may display the sediment quality of numerous water bodies on the geographic information system map. The original data may be downloaded as a reference for the water environment management, effectively understanding the historical patterns of the sediment quality changes in Taiwan.