Nutrient Retention: Question about water purification threshold table
I am having difficult understanding exactly what is being asked for in the threshold table. Many of the water quality standards that I have researched are reported in mg/liter, however the module is asking for kg/yr. Furthermore, because the module asks for thresholds per watershed, I am led to think that that number represents the total number of allowable kilograms in a watershed in one year--which is a figure I'm having difficulty finding at all. The sample data that comes with the module lists "2" and "1" for threshold N and P values, which seem low if that represents the total number of kilograms of N, for example, that are allowed in the watershed in one year's time. Any guidance would be much appreciated!