Oak Ridges Moraine - Hydrology

Hydrology

A number of features comprise the hydrological system of the Oak Ridges Moraine:

• permanent and ephemeral streams,
• wetlands,
• kettle lakes and ponds, and their catchment areas,
• seepage areas and springs, and
• aquifers and other recharge areas.

This hydrological system is inter-twined with a regional flow systems not bound by the morphological limits of the moraine. For this reason, environmentalists and researchers promote an aggressive protection strategy extending beyond the moraine, thus ensuring a contiguously protected hydrological system.

The preservation of aquifers is especially important, since they are used as a primary water source by some municipalities located on or near the moraine. These aquifers also discharge into tributaries that are the headwaters of creeks and rivers which eventually flow into Lake Simcoe, Lake Scugog and Lake Ontario.

The Oak Ridges Moraine Conservation Act stipulates that any development which targets the moraine or nearby areas must satisfy several conditions, most prominently that each development leave a buffer zone of 30 metres (98 ft) between it and any hydrological feature; for a kettle lake, this measure is from the edge of the lake's catchment area.

The Oak Ridges Moraine's hydrological system is a major constituent of the Humber Watershed, so that any factors affecting the moraine may have an impact on the connected systems. A specific concern is urbanization, which affects water quality by increasing its load of metals and organic contaminants. A study by Cook et al. (1985) found an increase in mean annual runoff, instantaneous discharge, and hydrograph peak flow as a result of urbanization: "...changes in land use coincided with changes in volumetric and time distribution aspects of hydrologic response".