The OPA and ZBA for this was approved by city council in January, with that said this (and pretty much every other project in KW) will not be going ahead anytime soon. This has a holding provision that states "a study determining adequate water supply capacity has been completed, or the Region of Waterloo Water Supply Master Plan and any necessary updates to water supply infrastructure have been completed."
This all stems from the water capacity issues that are currently plaguing KW (Cambridge is semi off the hook), there will be a substantial reduction in projects that are going to go forward for the next little while because of it, ZBA/OPAs may still go through but some developers are already pivoting construction to other markets given the situation.
I'll give a bit of an explanation on the whole thing because KWCs water supply is way different than most other major municipalities which are fed from one the Great Lakes. In KWCs case all the drinking water supply is groundwater from various wells throughout the Region and a surface water intake from the Grand River (25% of the supply). The system itself is known as the Integrated Urban System (IUS). The IUS is split into two different service areas, Mannheim and Middleton, Mannheim feeds KW, Breslau, Elmira, St Jacobs, a few small towns, and most of the East Side Lands of Cambridge, while Middleton feeds the rest of Cambridge. The two areas have some interconnects but they only exist for emergency situations and are limited to the Cambridge portion of the Mannheim area. Surplus water cannot be sent beyond that as there is no pumping infrastructure. The second issue is they use differing treatment methods, Middleton uses Chlorine for secondary decontamination and Mannheim uses Chloramines, generally speaking you don't want to mix them, you can but it can create quality issues.
Now the actually problem came to light as some of the wells have started to produce less water and the Region looked into it and discovered that the Region has been pumping more water than the aquifer can recharge in a year as such they've been slowly lowering the water levels. As such the Region changed their methodology to determine system capacity. The previous methodology was looking at the IUS (Integrated Urban System) as a whole, using maximum system capacity (MECP recommendation), and tracking sustainable capacity but not using it in calculations. The new methodology divides the IUS into two Service Areas; Mannheim and Middleton (since they can't interconnect currently), uses sustainable capacity and max capacity in calculations, and requires a 20% resiliency.
Another thing to note is Waterloo Region has done a surprisingly good job at water conservation to the point that the peaking factor of the system is the lowest of most municipalities in Ontario, which means Waterloo Region can't easily conserve more water. Waterloo Region also uses weekly data for peaking factor calculations but it still relays the same information. For some context MECP recommends 1.5, which most municipalities target in there plans and generally report around that value or above but it does fluctuate. The only similar municipality that is below 1.5 is Guelph at 1.34 compared to Waterloo Region at 1.24 (they're also the two largest areas that rely on groundwater).
Now since they changed to looking at sustainable capacity it meant that the amount of water the system has to use for supply has been decreased, in Mannheim there is 114,000 cubic meters of demand at present, supply is at 126,000 cubic meters, so there is capacity left in the system, however when including the 20% resiliency the capacity of the system falls to 101,000 cubic meters, which is below our existing demand hence the capacity problem. When including the additional approved developments into the system it makes the problem worse. In different terms the current treatment capacity of the Mannheim portion of the IUS is 1455 L/s when operating at 100%, with the 20% resiliency it drops to 1164 L/s, currently the system is operating at 1356 L/s. If we included all the approved applications within the treatment area your total jumps to 1592 L/s which there clearly isn't capacity for under the new method.
This basically means that if a major system were to go offline (ERB WTP, Strange WTP, or half of the Mannheim WTP) KW would be in a very rough situation. Similarly if the Grand River gets contaminated upstream of Hwy 8, or something within the surface pumping system fails the Mannheim WTP goes offline which isn't a good situation (Calgary type situation). With the old capacity method it would be relatively okay for awhile, but with the new calculations its not.
As such the Region has stopped signing off on developments until they have a plan in place to solve some of the issue (hence the holding provision). There are a few well groupings that the Region has (Woolner Wells, Lancaster Wells, Forwell Wells, and Pompei Wells) that aren't in service, those can be brought online with some work to provide some capacity relief. They have roughly 306 L/s of capacity (this is old data and with the updated method it will be way less) but it would ease some of the capacity issues. Long term this is likely going to be a pipeline to Lake Erie, there is a few test wells the Region is drilling in other areas of the Region but they aren't using them for pumping.
