Eutrophication is the single greatest impediment to effective, sustainable IWRM and Renewable Water. This is because eutrophication happens systemically, progressively and chronically, so it develops “a life of its own” as it appropriates feedback mechanisms that reinforce and entrench the eutrophic condition.
Eutrophication is a result of what is happening upstream but because it becomes an entrenched systemic condition in the downstream water body, addressing upstream causes might slow down the process, but cannot reverse it. This is because nutrients that have accumulated in a water body are recycled annually; weeds, algae and cyanobacteria bloom in summer, die off in winter and decompose to regenerate the nutrients needed for next year’s cycle. Weeds, algae and cyanobacteria become “well nourished” in eutrophic water bodies as they appropriate and dominate the Nutrient Cycle by recycling nutrients in the sediments and water column.
So remediation tactics such as reducing nutrient inflows are futile in the face of the recycling of “in-lake” nutrient stockpiles of Nitrogen and Phosphorus.
Similarly, tactics aimed at addressing symptoms such as removing sediments by dredging, bubbling air into the water, harvesting and removing invasive weeds and algae, or killing them with herbicides and algaecides are an equally futile game of “Whack-a-Mole”.
But without a solution to eutrophication that can re-establish harmony between the Water Cycle and the Nutrient Cycle, water resources will continue to degrade to the point that water cannot be used to produce potable water or to irrigate crops.
The Eutrophy Solution is therefore the “holy grail” and cornerstone of IWRM.