Now that you have identified all activities that fall within the basin, you will calculate their (combined) baseline. The baseline is the initial amount of pressure—water withdrawals or pollutant loading—that your activities have on the environment in the defined location (the water basin) before you start implementing any improvements.
Depending on how you completed Step 1b, you may have the baseline information already, but it is also possible you will have to recalculate it at this point with more accurate calculations.
Calculate or estimate the baseline of each individual site or activity in the basin.
Water quantity pressures from direct operations and point source water quality pressures must be calculated from primary data, which you can get from water meters or sensors. For all other pressures, primary data is recommended but not required (you can use secondary data if needed). Use data from the last five years of operations to calculate the baselines. If data for the whole period is not available, a duration of less than five years can be used. Once you start taking action in the basin to achieve your targets, you can replace any baseline estimated from secondary data with primary data.
Depending on your source of data, water withdrawals and pollutant loading can be measured (or estimated) with monthly data, annual data, or in terms of concentration. While it may be more time-consuming to obtain, monthly data enables you to set monthly targets, which allows you to focus your actions on the most important months, given seasonal water variability, and use your resources more efficiently.
From this point on, you must keep your primary and secondary data separated because in Step 5 you will use different methods to estimate progress depending on how you have measured your baseline. Remember that direct operations and upstream data must also be kept separate at all times.
Aggregate and record the baseline pressure generated by all activities in the basin.