There is an increasing number of restoration projects and land use mitigation actions aiming to improve stream water quality and ecological health across Aotearoa New Zealand. Monitoring the effect of these activities is not standard practice but is urgently needed. Many ecological indicators are highly variable and there are significant limitations to increasing monitoring frequency at a given site; as a result, these indicators must often be monitored for a long time at a single site to detect change. Our project aimed to model both spatial and temporal variability in ecological endpoint indicators to investigate the potential for substituting “space-for-time” when monitoring these indicators at a catchment scale. The outputs of the modelling are integrated into a web tool that enables end-users to select the degree of change in an indicator (Macroinvertebrate Community Index score, periphyton or deposited fine sediment cover) and output the number of sites and length of monitoring record (for the limited range of monitoring frequencies). This tool will guide the development of programmes seeking to monitor the effectiveness of restoration efforts and extend the current water quality indicators to include relevant stream health indicators. The tool has the ability to communicate realistic expectations of change detection from monitoring programmes and engage stakeholders in documenting outcomes from restoration projects.