However, in the same period, the proportion of phosphates from agricultural diffuse has increased despite the efforts of the Environment Agency, NFU, CLA and Farm Herefordshire.
Earlier this year, the Wye was affected by the algal bloom, and councillors believe that some of the conditions that produce the bloom such as sunlight and water temperature will become increasingly frequent due to climate change.
The proliferation of poultry units in Powys has also come under scrutiny. Councillors say they are an important element because they are in the upper reaches — the severity of the algal bloom is dictated by the length of time the algae has to divide in the water.
Phosphate is also coming off top-dressed grassland, arable (particularly maize and other bare-soil crops), and from livestock units.
Nutrient management board chairman Elissa Swinglehurst said: “We all need to do our bit to stop this from happening.
“It’s not an impossible task, but we do need to work together as regulators, councils, farmers, housebuilders, water companies to save the Wye and we need to do it now.
“What I want is that when it rains I will not be seeing brown floods taking soil and valuable nutrient off compacted fields and into the watercourses.“This year, I had fields near me where so much soil washed off it needed a loader to clear a path to local houses. All of the nutrients went straight into a Wye tributary which discharges into the Wye at a point where there is a peak in phosphate levels.
“So many farmers are doing the right thing – they are looking after their soil, taking care of the river, fulfilling their role as guardians of the countryside, but, sadly, some are not.
“I beg those farmers to stop being part of the problem and start being part of the solution.
“For all our sakes, for the sake of the river, the countryside and the future generations who will want to live and farm in the beautiful county of Herefordshire.”