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Flood Control
Flood Forecasting and WarningCurrent Conditions
Fee Schedule for Conservation Services - Sandbags and Pumps The Lower Thames Valley Conservation Authority provides flood advisories and warnings to municipalities and individuals in flood prone areas. The reaction of streams to a climatic event and the impact on flood prone areas is determined by monitoring weather conditions and the stream gauging network on the Thames River and Indian/McGregor Creek. The LTVCA provides a coordinated response to flooding in the lower Thames region. We use a flood contingency plan and have the expertise and understanding of the geography and river dynamics. We monitor and evaluate weather conditions and river flows on ice jams. The LTVCA is in communication with the Upper Thames River Conservation Authority and the Aviation, Flood and Management Branch of Ontario Ministry of Natural Resources.
History of FloodingSevere flooding throughout Ontario in the late 1930’s and early 1940’s led to the formation of the Conservation Authorities Act in 1946. Within the Lower Thames Valley Conservation Authority (LTVCA) watershed, flooding problems have frequently occurred. In the lower Thames River watershed, there are very large areas of floodplain beside the river. These areas have historically been developed during periods of infrequent flooding and subsequently protected by dyking during times of more frequent flooding. As upstream agricultural landuse has gradually changed from general farming to a more cash crop intensive system, the speed of runoff water and the frequency of all degrees of flooding has increased. However, due to the topography of the lower Thames valley, the flooding is relatively shallow and of a low velocity. There are also lands within the LTVCA bordering on Lake Erie and Lake St. Clair which have been developed during periods of low lake levels and subsequently dyked and drained during periods of higher lake levels. These areas are most prone to flooding during periods of high lake levels when winds generate high waves. Waves also quickly erode and breach the protective dyking. One of the prime initiatives behind the formation of the Lower Thames Valley Conservation Authority was to solve the flooding problem. Major flood events along the Thames River occurred in 1937 and 1947. These two almost identical flooding events Heavy rainfall, melting snow and river ice jams may cause water levels in streams and rivers to rise higher than the banks. Many low-lying areas along the lower Thames River and its major tributaries are especially prone to flooding.
LTVCA’s Flood Control Program
Flood Prone Areas1. Approximately 9,000 hectares of low lying dyke protected agriculture lands and auxiliary homes in the areas previously known as the Townships of Dover, Tilbury North, Tilbury East and Raleigh are prone to ice jam flooding. 2. The entire village of Thamesville, the low lying areas along the Thames River in the City of Chatham, as well as about 9,000 hectares of agricultural land abutting the Thames River from Chatham to the Kent/Elgin boundary are all subject to flooding from high Thames River flows. 3. Approximately 650 hectares of agricultural land in the area previously known as south Harwich as well as lakeshore abutting homes in south Harwich, Erie Beach and Erieau are prone to high lake level flooding. 4. The Lighthouse Cove area is an undyked residential area at the mouth of the Thames River, which is prone to flooding from ice jams in the Thames River as well as flooding from high lake levels.
Fee Schedule for Conservation Services - Sandbags and Pumps Water Control StructuresOperation and Maintenance - Dams, Dykes and Diversion Channels ... Water Control Structures to Protect YOU The lower Thames River has a long history of flooding. The LTVCA has developed the expertise and understanding of the geography of the region, the nuances of the Thames River and its reaction to natural or man-made interference. In fact, one of the primary reasons for the founding of the LTVCA was to provide a coordinated response to the flood problem. The most visible works of the LTVCA, including dyking and diversion channels, revolve around the flooding problem. The operation of water control structures helps to ensure a coordinated response to flooding problems. The Lower Thames Valley Conservation Authority operates and maintains Conservation Authority owned water control structure, primarily the Indian/McGregor Flood Control Project.
Indian/McGregor Creek Flood Control ProjectThe Indian and McGregor Creek watersheds drain over 27,000 hectares of land in the southern area of the Municipality of Chatham-Kent, making it one of the largest watersheds within the LTVCA’s jurisdiction. The McGregor Creek has its headwaters in the village of Highgate and the town of Ridgetown. It flows generally west through the previously named townships of Orford, Howard and Harwich until it reaches Kent Centre, where it flows north to Chatham. The Indian Creek flows north from Blenheim through the previously named Raleigh Township to the outskirts of Chatham. It then flows east to join with the McGregor Creek. Flooding first became an issue in the early 1900’s, with runoff and backup flooding from both creeks affecting the Municipality of Chatham-Kent. Runoff flooding occurs as a result of heavy rainfall, sometimes accompanied by melting snow. It has increased over the years due to the loss of forests, changes in farming operations and improved drainage practices. Backup flooding results when significant runoff in the Thames River watershed reached Chatham. The water levels rise and ‘backup’ through the McGregor Creek, submerging the same flood prone area. One of the most vulnerable flood-prone areas is along Indian Creek in Chatham and surrounding areas in the previously named Townships of Harwich and Raleigh. Both runoff and backup flooding affect these areas. Under runoff conditions, flows on McGregor Creek are high enough to backup Indian Creek and flood a large, urban area. Channel restrictions on McGregor Creek in Chatham also reduced the capacity for flow in the creek. The Indian / McGregor Creek Flood Control Project is designed to reduce flood risk in south Chatham and the surrounding areas of the previously named Harwich and Raleigh Townships, and to provide an adequate outlet for the McGregor watershed. The Indian/McGregor Creek Flood Control Project was initiated in 1968 to deal with this recurring problem. Following a four-year investigation, construction began to improve the outlet capabilities of the Indian and McGregor Creeks. However, these improvements were insufficient in handling excessive runoff flows and in 1984, the project became the subject of an Environmental Assessment. The Assessment’s purpose was to determine the best possible location for a diversion channel to handle the high runoff flows. An upstream location was selected to divert a majority of McGregor Creek’s water flow through high land. In 1989, after an agreement was made with the eight municipalities concerning cost distribution, funding was received from the Province of Ontario, and construction began. The 3.3 km long channel which borders the eastern boundary of Chatham was completed in 1991. A backwater control and pumping station, situated near the mouth of the McGregor Creek, achieved completion the following year. The final cost of the Indian/McGregor Creek Flood Control Project was 16.2 million dollars. This sum was 10 percent below the amount budgeted. Subsequently, the Municipality of Chatham-Kent will experience over 30 million dollars worth of benefits and possible flood damage to 2,000 homes and businesses has been eliminated
The Diversion Channel – Indian McGregor Creek Flood Control ProjectA
The Backwater Control Dam and Pumping Station – Indian McGregor Creek Flood Control ProjectThe backwater control dam and pumping station are situated near the mouth of McGregor Creek. The backwater control dam has 4 gates, each measuring 3 m by 5 m. The gates are only closed when water in the Thames River is high. This prevents Thames River water from backing up into the flood prone area. The pumping station, which is adjacent to the backwater control dam, houses a battery of submersed electric pumps. When the gates on the backwater control dam are closed, these pumps force nominal drainage water from the Indian Creek over the dam and into the swollen river. The pumping station has the capacity to pump 8.5 cubic m of water per second. The back water control dam and pumping station were completed in 1992 at a cost of $2.7 million.
Improvements to upstream sections of Indian Creek, Gregory Drain and McGregor Creek bring these channels to a consistent and acceptable capacity for runoff. Enlargement of the culvert on Indian Creek at Queen St. and improvements to the McGeachy Farm bridge were completed in 1993. Including the improvements to the upstream section of the McGregor Creek, the cost of these other project components is $2.5 million.
Federal-Provincial Dyking ProjectFrom a low cycle in 1964, Lake St. Clair rose to record heights in 1973 resulting in many e
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occurred as a result of heavy springtime rainfalls. These two floods were equivalent to floods, which should occur once every one hundred years. Since the Conservation Authority was formed in 1961 most of the major flood events of 1968, 1979 and 1985 have been associated with relatively high river flows and ice jams. Ice jam flooding affects large areas of agricultural land downstream of Chatham. The ice jam flood of 1985 inundated approximately 5600 hectares in four townships. The high lake level periods of 1973-1974 as well as 1985-1986 also produced flooding in lake abutting lands. The rapid rates of dyke erosion as well as wave attack on homes during severe onshore winds are the main problems faced at these times.
The LTVCA’s flood control program involves the operation and maintenance of water control structures and flood forecasting and warning. This program reduces the impacts of flooding through prevention and structural controls to prevent the loss of life, to minimize property damage and social disruption and to encourage a coordinated approach to land use and water management. Flood control has many community benefits including the minimization of financial and social costs to the residents within the LTVCA’s watershed and the reduction of the effects of erosion to buildings and soil.
major project component is a diversion channel, 3.3 km in length, generally located along the eastern boundary of Chatham. This channel has a top width of about 50 m and depth of approximately 6 m. A gated inlet structure is located on McGregor Creek at the entrance to the diversion channel. This inlet structure contains gates, which close under runoff conditions on McGregor Creek. Closing the gates forces runoff water from the McGregor Creek down the diversion channel. Under normal flow conditions, the gates are open and allow these flows to go down McGregor Creek. The diversion channel is grass lined and dry throughout the year except during flood periods. Halfway along the channel is a 12 hectare disposal site, a parcel of land containing excavated material from the channel. The diversion channel, completed in 1991, cost $11.1 million.
mergency dyking and excavation projects to hold back Lake St. Clair from the Thames River to the Sydenham River. Recognizing the problem, the Province of Ontario and the Federal Government undertook a joint dyking program in the mid to late 1970’s. During this time in the Lower Thames Valley Conservation Authority, approximately 56 kilometres of 
