To reduce our overall water requirements, we maintain high produced water recycle rates (90-99 per cent) throughout our major thermal in situ, and polymer flood and waterflood operations. At our Horizon Oil Sands operation, since the start of operations in 2009, we have decreased water use intensity by half. Canadian Natural has also advanced industry knowledge for the cost effective treatment of tailings water, which will help us to reduce fresh water use Read our 2015 Stewardship Report to Stakeholders for information on our water use and performance.
At Horizon we also limit fresh water withdrawals from the Athabasca River to less than one-third of our regulated allocation. We work with other oil sands operators to manage water withdrawals to ensure the ecology of the Athabasca River is protected. Horizon features an on-site water storage pond that holds enough water for up to 30 days that allows us to maintain production in the event of water withdrawal restrictions during the river's low flow periods. Additionally, different water treatment options are being reviewed to further reduce our fresh water consumption.
In our Southeast Saskatchewan and Manitoba enhanced oil recovery operations, we use water from a brackish aquifer for waterflooding purposes. Canadian Natural’s Septimus unconventional natural gas operations in northeast British Columbia also utilizes produced water from the plant for hydraulic fracturing operations and recycles nearly 100% of the water to drill subsequent wells.