The sheet “Monthly and seasonal conc” already presents 5 case studies with flow-weighted sampled concentrations every month for a year, which is considered unique. These have now been adjusted with additions for total concentrations and an introductory table that presents calculated average percentages of total annual concentrations that a month or season gives.
Examples of use:
A stormwater sampling has taken place during the summer and it is desired to get an estimate of which annual average concentrations this corresponds to, taking into account whether there are higher or lower concentrations during the summer than the annual average. Based on the percentages in the table (e.g. 117% of P during the summer compared with the annual average), it is possible to roughly (!) calculate which annual average concentration the sampled concentrations are deemed equivalent, e.g. which annual average concentration of the sampled concentration 120 ug/l P corresponds to as annual average value.
These recalculated annual average concentrations, e.g. 120 / 1.17 = 103 ug/l, can then e.g. be used in StormTac Web to replace estimated values from the area where sampling took place. Then these can be used to calculate pollutant loads, design treatment facilities, etc., taking into account the site-specific conditions. This presupposes that the sampling took place in proportion to the flow with a sufficient number of collected samples (we recommend at least 7 samples).