The Regional District has, since at least 1981, regulated development within the floodplain associated with Osoyoos Lake through its zoning bylaw and designated the “floodplain” as being any area with an elevation lower than 280.70 Geodetic Survey of Canada (GSC) datum.

These regulations have further required that the floor system or pad which supports a habitable area (e.g. the underside of the wooden floor system), is not lower than the flood construction level, which is generally the 200-year flood level shown on available provincial mapping.

The provincial mapping that the Regional District has relied on to apply these regulations was prepared in the late 1980s.

In 2020, the Okanagan Basin Water Board (OBWB) completed the Okanagan Mainstem Floodplain Mapping project, which involved the development of updated floodplain mapping.  

In early 2026, the Town of Osoyoos adopted amendments to its Official Community Plan (OCP) and zoning bylaws to increase the floodplain elevation of Osoyoos Lake within the Town’s municipal boundaries from 280.70 metres GSC datum to 280.80 metres GSC datum based on the recommendations contained within a Flood Mitigation Plan (2022) completed by TRUE Consulting Ltd (which incorporated data from the 2020 OBWB floodplain mapping project).

The Okanagan Valley Zoning Bylaw No. 2800, 2022, currently sets out floodplain regulations which apply to Electoral Areas "A", "C", "D", "E", "F", and "I" (i.e., the Okanagan Valley electoral areas) under Section 10.0 (Floodplain Regulations) of the bylaw.

These regulations include:

• the designation of floodplain areas (via Provincial maps for the floodplain areas associated Okanagan River and Okanagan River Channel, and text for all other floodplain areas);
• the establishment of flood construction levels applicable within the designated floodplain areas;
• building/structure setbacks from watercourses;
• how flood construction level is measured; and,
• various regulations pertaining to the construction of habitable areas and other types of buildings/structures.

The floodplain areas associated with Osoyoos Lake are designated via the Provincial floodplain maps for the Okanagan River and Okanagan River Channel. The associated flood construction level is established as 280.70 metres GSC datum under Section 10.1.2(g) of the Zoning Bylaw. These designated floodplain areas are currently subject to development regulations under Sections 10.2 and 10.4 of the Zoning Bylaw.

Building and structure setbacks under Section 10.2.3 currently applies as follows:

• 7.5 metres of the natural boundary of any lake, pond or marsh, or the top of bank where the bank is within 7.5 metres of the natural boundary of any lake, pond or marsh.

Section 10.4 of the Zoning Bylaw currently applies to these designated floodplain areas and sets out how habitable area (and other specified types of buildings) is to be constructed within a floodplain.

As Osoyoos Lake is situated within both the Town of Osoyoos and Electoral Area “A” in the RDOS, it is being proposed to update the floodplain elevation of Osoyoos Lake from 280.70 metres GSC datum to 280.80 metres GSC datum to ensure consistency between the two jurisdictions.

Zoning Amendment Bylaw No. 2800.64, 2026 proposes amendments to Section 10.0 (Floodplain Regulations) of the Okanagan Valley Zoning Bylaw No. 2800, 2022 in order to update existing floodplain regulations associated with Osoyoos Lake and to replace the existing provincial floodplain mapping with a new, updated floodplain map.