Custom functionality has been created for some states. In these cases, the sidebar will display these as optional functions after completing a delineation. For example, a special function that tests for the presence of upstream regulation from dams has been developed for Colorado and Montana. Also, a special function that provides a summary of water withdrawals and discharges within a delineated basin is available for the Delaware River Basin and northeastern Ohio. These special functions must be used prior to selecting the Continue button within the Basin Delineation sub-panel, as the State/Region Specific Functions panel will disappear after clicking on Continue.

The test for upstream dams for Colorado is illustrated below. In this case, after the basin delineation is completed a button labeled Check for upstream regulation appears within the State/Region Specific Functions sub-panel. Clicking on this button will run a process that identifies the locations of any upstream dams, computes the drainage area upstream from the dams and the drainage area downstream from the dams. Finally, it displays the areas upstream from the dams in orange on the map and lists the percentage of the watershed that is affected by dam regulations in a green text box in the sub-panel.