Ski boats a culprit
You can put mats loaded with plant material in lakes and rivers, but until the real problem is addressed, it is like trying to heat the outdoors in midwinter.
The most phosphates come from the soil disrupted by ski boats designed to make ever larger wakes. The operators have also discovered that adding up to 10 or 12 passengers on the stern will make an even larger wake. When these waves hit the shore, they erode the shoreline, thereby stirring up dirt, which contains phosphates, thus loading the river with more phosphates in one pass than all people living along the shoreline fertilizing all summer.
Undoubtedly, these boats should be outlawed anyplace there is a phosphate problem, such as the Coeur d’Alene lake and river systems, including the Spokane River. There should also be a no-wake zone for boats over 26 feet in length for the entire river system.
Our local and state leaders have long known this but have consistently dragged their feet in confronting the problem. They corrected this along the Coeur d’Alene and St. Joe rivers some time ago in not allowing towing on weekends and no-wake zones where the riverbanks are eroding.
A trip up and down the Spokane River between Post Falls and Coeur d’Alene will show the banks eroding, trees falling and dirty (phosphate loaded) water. Property owners are also overburdened with repairs caused by this activity.
The Coeur d’Alene and Post Falls sewage treatment plants consistently take the blame for phosphate loading that is simply not of their doing. It is time for our commissioners to take action.