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Geothermal Cooling works best with subsurface draw outlets (1.2 m or deeper) that provide cooling of the higher flows and would be less expensive than installing additional boreholes (at least in new builds). When sized appropriately, geothermal systems can shave a few degrees off of the average pond outflow temperature.
Geothermal Cooling works best with subsurface draw outlets (1.2 m or deeper) that provide cooling of the higher flows and would be less expensive than installing additional boreholes (at least in new builds). When sized appropriately, geothermal systems can shave a few degrees off of the average pond outflow temperature.
==Other Options==
Vegetated channels installed downstream of pond outlets can help to reduce temperatures through shading, although typically a long channel is needed to have an appreciable benefit on temperatures.
Underground detention chambers, have the potential to cool inflowing runoff and maintain temperatures suitable for discharge to cool water fisheries (Drake et al, 2015)<ref>McIntosh, N., Drake, J., Young, D. and Spencer, J. 2015. Modeling Sedimentation in Underground Stormwater Detention Chamber Systems. In International Low Impact Development Conference 2015: LID: It Works in All Climates and Soils (pp. 43-52). https://sustainabletechnologies.ca/home/urban-runoff-green-infrastructure/low-impact-development/soakaways-infiltration-trenches-and-chambers/evaluation-of-an-underground-stormwater-detention-chamber-system-in-markham-ontario/</ref>
Surface cover also has the potential to provide cooling benefits. Options include floating islands, solar panels, shade balls, trellis infrastructure to support vines and south shading of east west oriented ponds with trees. The data from various studies shows that surface cover needs to cover more than 70% of the pond with an opaque surface material to promote appreciable temperature reduction benefits. Trees on the banks of ponds will not provide immediate thermal benefits as they will take time to grow, but are otherwise an excellent long term strategy.
===Shade balls===
<ref>Rocha, L., and VanSeters, T.2020. Evaluation of shade balls for mitigating summer heating of stormwater management ponds. Toronto and Region Conservation Authority, Vaughan, Ontario. https://sustainabletechnologies.ca/home/urban-runoff-green-infrastructure/thermal-mitigation/evaluation-shade-balls-mitigating-summer-heating-stormwater-management-ponds/</ref>
Ponds with large length to width ratios, oriented east-west with shading on the south side can also provide shading, although it will take several years for the shade to become established.
==References==
==References==