The flood plain is in the Hatzic Watershed, approximately 253ha (6255 acres). Hatzic Lake is approximately 337ha (1986 data – the lake has filled in a lot since then). This area is protected from in-flooding of the Fraser River by the dike maintained by DAID.
The boundaries of the Improvement District are the flood height of the largest flood on record which occurred in 1893. The present dike is constructed to this level plus ½ meter.
The present dike was constructed after the devastating floods of 1948. Prior to that, the CPR rail bed formed the major portion of the dike. After 1948, the CPR determined that their rail bed would not be used as a dike and the pres
ent dike was built along the Fraser River now also protecting lands south of the railway tracks.
The old pump station, which disappeared during the ’48 flood, was replaced with the present system of two pumps and floodgates. At this time, the railway trestle was shortened and soon replaced by three culverts.
The operating authority was then the Dewdney Diking District, which was subsequently replaced, under letters patent, by the Province of British Columbia in 1972 by the Dewdney Area Improvement District.
Since 1948, there have been no Fraser River floods. However, significant flooding occurs to parts of Hatzic Island and Hatzic Prairie due to the volume of internal water coming off the surrounding watershed and overwhelming the capacity of the system. This problem is exacerbated by infilling of the lake and the drainage creeks with sediment from the surrounding mountains. Slides on the mountains, particularly in the Patterson Creek drainage, have significantly reduced the water carrying capacity of the lake and creeks. These slides have occurred in old logged areas.
The Provincial Government used to keep the waterways cleaned out but this has not happened in the last while. The infill to the waterways and Hatzic Lake is ongoing from the drainage of the watershed surrounding the flood plain.
The Fraser Valley Regional District is presently trying to get the waterways cleaned out as many homes and farms are subject to chronic flooding. Work in the creeks is restricted to a small window during the summer months, (federal Fisheries regulations), and conditions have to be just right or the project is cancelled.
While the clean out of the creeks and even the lake, will reduce the frequency and severity of the internal flooding, it will not eliminate it. An increase of pumping capacity by four times with a similar increase in flood box relief would be required, along with the creek and lake clean out, before flooding would be all but eliminated. At this time, the cost estimate to do this work is in the multi-milliondollar range and beyond the tax base of DAID. The board is constantly pursuing avenues to secure funding to achieve these goals.
The creeks will require regular maintenance and clean out. This is not within the mandate of DAID. It will require a special benefits area to be established by the Fraser Valley Regional District in order to cover these costs.
DAID will continue to work with all levels of Government to find solutions to flooding.