RESEARCH on human adjustments to 1972 and earlier floods in the Rondeau-Erieau and Pelee-East Marsh areas (Figure 1) on the north coast of Lake Erie reveals:1. That significant ecological elements and processes associated with flooding are not well understood by resource managers and the public.2. That a relatively narrow range of expensive engineering (structural) adjustments has been used in attempts to control flooding and related ecological elements and processes.3. That such adjustments have generally been introduced in a crisis atmosphere, during periods of high-water level on Lake Erie. 4. That financial and institutional arrangements have been developed to support perpetuation of engineering adjustments, notably by spreading their cost among increasing numbers of Canadian taxpayers.5. That no detailed evaluation of the economic, social, or biophysical (environmental) benefits and costs of these adjustments has been undertaken by any government agency associated with their use.6 . That engineering adjustments generally appear to be justified on the grounds that they promote food and agricultural production, but without adequatc evaluation of: ( 1 ) returns which could be derived from comparable public investment elsewhere (opportunity costs) ; ( 2 ) the discriminatory character of the investments; ( 3 ) the recreation and environmental costs of using engineering adjustments, or the "technicological fix"; (4) alternative adjustments, including land use controls.A number of recommendations are made as a result of our research: 1. Impending large-scale diking and other engineering projects especially on marsh lands along the north Erie shore, Lake St Clair, and the Lower Thames should not go forward until detailed benefit-cost and environmental impact studies are carried out and further careful consideration has been given to hazard insurance, land use controls, and other alternative adjustments. I 0 6 30 FIGURE 1. Rondeau-Erieau and Pelee-East Marsh study areas. The arrows indicate the direction of erosion and depos THEFALL 1 9 7 2 L A K E E R l E F L O O D S 37 3.No large-scale drainage, flood, or erosion control schemes should be undertaken in Ontario in future without evaluating a wide range of alternative adjustments and their economic, social, and environmental benefits and costs in the manner just described. 4. A detailed review of policy, legislation, and institutional arrangements relating to drainage, flood, erosion, and other adjustments should be initiated in the near future, notably with respect to coastal lands. In this review, especially careful consideration should be given to: ( 1 ) reducing the proportion of senior government financial subsidy for structural and other hazard adjustments; (2) introducing guidelines for the use of senior government hazard funds at the municipal level.5 . Consideration should also be given to other policy and institutional changes, including: ( 1 ) public purchase or land use control of coastal lands identified as very susceptible to flooding, erosion, and mars...