Environment

One major water contaminant that we control onsite is sediment. Too much sediment in water has negative effects on aquatic life such as

• Blocking fish gills
• Effect fish and macroinvertebrate feeding patterns and growth
• Irritates fish skin
• Kills fish and macroinvertebrates
• Destroys fish and macroinvertebrate habitats by changing the river bottom substrate size i.e. gravel to silt based
• Displaces and changes ecological communities

AB Lime knows that one of the main sources of sediment into the water is the blending and dispatch area.  A sediment control constructed wetland in place to assist in removing most of the sediment and any nutrients in the water before it exits the AB Lime property. AB Limes resource consent states that they must capture at least 75% of all sediment in water before it exits the property and the wetland helps to achieve this standard.

During rainfall events, sediment loaded runoff from this area is directed and collected into a series of sediment traps and ponds. It then drains into a sediment control S-bend wetland which slows the flow of the runoff allowing the suspended sediments a better chance to settle out on the bottom.

The current wetland has been in place for over 20 years! Originally this area was simply a series of S-bend channels and ponds with no planting here designed to purely reduce sediment from runoff. Although the wetland is still very effective in reducing the sediment load from runoff AB Lime is working to improve the wetlands efficiency to combat other water quality concerns and to also increase native biodiversity.. To help reduce nutrients and to boost native biodiversity AB Lime has begun to restore the wetland by planting native vegetation. This extra vegetation take up more nutrients and will modifying the channels and ponds to further slow water flow help improve water quality further.