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Report calcuates $11M bill to prevent future flooding near Oliver

A report on a South Okanagan watershed estimates it could cost upwards of $11 million to handle a one-in-200-year flooding event.

The Park Rill watershed is located near Oliver. In 2018, it experienced extensive flooding, with the most impacted areas being the Willowbrook and Sportsmens Bowl Road areas.

The flooding caused damage to homes and public property.

The report was created by Ecora Engineering and Resource Group Ltd. and Dobson Engineering Ltd., which were tasked by the Regional District of Okanagan-Similkameen (RDOS) with a feasibility study regarding long-term flooding solutions in the area.

A view of Sportsmens Bowl Road near Oliver, B.C.

According to the report, “flooding in the Park Rill area resulted in considerable expenditure for pumping and temporary flood protection works, implemented by the RDOS EOC and funded by Emergency Management BC.

“Repeated flooding of infrastructure in the Park Rill Creek watershed has been documented since the 1950s.”

The report, which can be viewed here, lists options for flood management.

The document also states that for the proposed works to be implemented, “a drainage service area would need to be established through public consent under the jurisdiction of the RDOS, which would define the hydraulic structures and channel reaches, where maintenance and repair works would be the responsibility of the RDOS and financed through annual taxation.”

The report said that considering spatial constraints, there are two main options to mitigate flooding within the Park Rill Creek watershed.

Option 1

  • Upgrade Park Rill Creek to handle the one-in-200-year event, including channel improvements within Willowbrook and Sportsmens Bowl Road, upgrades to public road crossings and increased capacity at Okanagan River with the construction of an eclectic pump station.

Option 2

  • Provide storage to attenuate peak flows up to a one-in-200-year event in Myers Flat and maintain a peak discharge equivalent to the existing channel capacity downstream of the dam. The construction of a dam directly downstream of Myers Flat could provide the necessary attenuation to maintain manageable peak flows, which would significantly reduce the cost of channel and crossing upgrades, and works required at the outlet to Okanagan River would be significantly reduced as a result of a lower peak flow rate. Channel and road crossing upgrades would still be required upstream of the dam in this option.

The report, which spanned 94 pages, also said: “Consultation with the private property owners that would be affected by the proposed works would be required to discuss responsibilities of all parties and inform residents of the potential financial impacts that these upgrades would impose.”

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