Flood Damage Centre is a name given to areas where flooding occurs. Historical flooding is recorded by the Conservation Authority and has assisted in identifying where flood plain mapping studies should be completed.
LIDAR data is a relatively new way of collecting ground surface elevation data with enough accuracy and precision to map regulatory flood lines and replace most manual ground surveying required for projects like these. It is collected by a device on an airplane measuring the rate at which light emitted by a laser is reflected off surfaces below it. The light, however, does not reflect off of water and is absorbed, so manual surveying is still required for watercourse areas. If you are interested in obtaining this data from the City of Kawartha Lakes for a future project, please contact the City of Kawartha Lakes or Kawartha Conservation to be directed appropriately.
Models are computer programs which receive a number of inputs from a study area such as; LIDAR data, manual surveys, land use, rain data, longest flow paths, culvert sizing, etc. By using this data, they calculate the ways a stream or river will react in a flood situation. There are both hydrology and hydraulic models. Hydrology models calculate and model the way the rain gets into the watercourse and flows downstream. Hydraulic models calculate and models the way the water in the watercourse is affected by culverts and other impediments and determines the flood elevations.
Regulatory Flood Lines are the extents (areas) of flooding calculated by the computer models during a regulatory storm. A regulatory storm is the largest storm an area could expect at the time of study development. This storm can be either a large historical storm or a theoretical storm using local rain data to estimate the worst storm which could occur in 100 years. In some cases, one of these storms may produce more flooding in certain areas than another. In this case, the regulatory flood lines would be a combination of both of the storms flood lines combined.
Two-Zone Approach is where the flood plain is conceptually divided into two main components; the floodway and the flood fringe. The floodway is the portion of the flood plain where flood depths and velocity pose a high risk for people and property. In this area future development and site alteration would generally not be allowed. The flood fringe is the portion of the flood plain where flood depth and velocity are lower risk and future development could be allowed subject to flood reduction and protection measures as well as any other work required to support safe development. Two-zone approaches are unique to each area and therefore policies need to be developed to reflect the issues in these areas.