River & Stream Systems: Flooding Hazard Limit - …

1 20021 Technical Guide - River and Stream Systems: Flooding Hazard LimitOntario Ministry of Natural ResourcesTechnical GuideRiver & Stream Systems: Flooding Hazard LimitOntario Ministry of Natural ResourcesWater Resources Section300 W ater Street, 5th Floor, South Tower, Box 7000 Peterborough, Ontario K9J 8M5 20022 Technical Guide - River and Stream Systems: Flooding Hazard LimitOntario Ministry of Natural ResourcesContentsA: 8 Acknowledgement .. 7B: POLICIES AND PERFORMANCE STANDARDS1. 102. PROVINCIAL NATURAL Hazard Natural Hazard Policies .. Provincial Interests - Flooding hazards .. Flood Standards for River Systems .. Flood Hazard limits for Lakes < 100 sq. km.. Official Plan Flooding Hazard Limit Policies .. One Zone ConceDpt .. Two Zone Concept .. Special Policy Area Concept .. Access and Floodproofing .. Safety .. 143. DEFINITIONS OF THE Flooding Hazard Introduction .. Selecting the Flood Standards .. Historical Storms.

2 Return Period Floods .. 164. SPECIAL FLOOD Hazard Flood Hazard Standards Downstream of aControl Structure .. Dams .. Dykes and Flood Walls .. Bridges and Culverts .. Confluence of Lakes, Rivers and Streams .. Confluence of Rivers .. Floodproofing of Buildings .. StormWater Management Ponds5. DESIGN STANDARDS FOR DAMS ..186. DESIGN STANDARDS FOR 19C: HYDROLOGIC AND HYDRAULIC PROCEDURES1. General .. Floods Based on Exceedance Probability of Occurrence .. Flood Produced by a Specified Meteorological Event .. Observed Floods .. 202. DATA Streamflow Records .. Historical Floods .. Specified Meteorological Event .. Stage-Discharge Relationships .. Hydraulic Coefficients .. Elevations of High Water Marks .. Aerial Photographs .. Cross-Section .. Regulated Flows .. and Physiographic Data .. Levels .. 233. FLOOD Flood Frequency Analysis .. Runoff Simulation From a Specified Meteorologic Event.

3 264. HYDRAULIC Type of Flow .. Cross-Sections .. Critical Depth .. Velocity Distribution .. Roughness .. Use of High Water Marks .. Plotting Routines .. Bridge Losses .. Culvert Losses .. Channel Flow .. Factors .. 29D: FLOW COMPUTATION DATA REQUIREMENTS1. RAINFALL Introduction .. Historical Storms .. Return Period Storms .. Probable Maximum Rainfall .. Snowmelt and Winter Precipitation .. 442. SOIL 493. LAND 50 20023 Technical Guide - River and Stream Systems: Flooding Hazard LimitOntario Ministry of Natural ResourcesE: METHODS OF COMPUTING FLOOD FLOWS1. 512. HYDROLOGIC Types of Hydrologic Models .. Computational Procedures Used in Models .. Recommended Model Selection .. Model Calibration .. 59F: WATER LEVEL COMPUTATIONS - OPEN WATER1. 612. BACKWATER 613. FLOOD 614. CHOOSING A HYDRAULIC MODELLING 625. RESERVOIR 646. EFFECT OF LAKES AND 647. WATERWAY CROSSINGS AND 658.

4 MODEL 659. TESTING AND 66G: WATER LEVEL COMPUTATIONS - ICE JAMS1. 672. ICE JAM 693. SUMMARY OF ICE JAM COMPUTATION 744. STAGE-FREQUENCY OF ICE JAM FLOOD Historically Based Estimates .. Deterministic Estimates .. Annual Flood Stage Probability Distribution .. 795. PROCEDURE FOR ESTIMATING THE FREQUENCYOF ICE-EFFECT 796. DATA COLLECTION FOR ICE-EFFECT 817. 82H: TECHNICAL REPORT AND DOCUMENTATION1. TECHNICAL 83I: IMPLEMENTATION OF FLOOD PLAIN POLICIES AND MAPPINGJ: SURVEYS AND MAPPING Under review 20025 Technical Guide - River and Stream Systems: Flooding Hazard LimitOntario Ministry of Natural ResourcesAPPENDICESAPPENDIX 1 BIBLIOGRAPHYAPPENDIX 2 GLOSSARYAPPENDIX 3 APPLICATION TO CHANGE THE FLOOD STANDARD WITHIN A WATERSHEDAPPENDIX 4 APPLICATION OF THE TWO ZONE CONCEPTFACTORS TO BE CONSIDEREDAPPENDIX 5 SPECIAL POLICY AREAS, FACTORS TO BE CONSIDEREDAND PROCEDURES FOR APPROVALAPPENDIX 6 FLOODPROOFING 20026 Technical Guide - River and Stream Systems.

5 Flooding Hazard LimitOntario Ministry of Natural ResourcesImagesLIST OF TABLESNATURAL Hazard POLICIES AND STANDARDSTABLE B-1 DESIGN RETURN PERIOD IN YEARS (T)FOR DIFFERENT DESIGN LIFE AND RISK VALUESTABLE B-2 DESIGN FLOOD CRITERIA FOR ONTARIO DAMSTABLE B-3 DESIGN FLOOD FOR ROAD CROSSINGSFLOW COMPUTATION DATA REQUIREMENTSTABLE D-1 COMPARISON OF STORMS USED FORFLOOD PLAIN AND PROBABLE MAXIMUMPRECIPITATION COMPUTATIONTABLE D-2 HURRICANE HAZEL RAINFALL DEPTHSTABLE D-3 HURRICANE HAZEL - AREAL REDUCTIONTABLE D-4 TIMMINS - RAINFALL DEPTHSTABLE D-5 TIMMINS - AREAL REDUCTIONTABLE D-6 RAINFALL DISTRIBUTIONS (PERCENT)TABLE D-7 ONTARIO VALUES FOR PARAMETER a (minutes)TABLE D-8 AES SNOWMELT EQUATIONSTABLE D-8 ONTARIO SOIL SURVEYSMETHODS OF COMPUTING FLOOD FLOWSTABLE E-1 ALTERNATIVE METHODS OF FLOOD AND WATER ..LEVEL CALCULATIONSTABLE E-2 COMPUTATION OF DIFFERENT CRITERIA FLOODSTABLE E-3 SUMMARY OF 100 YEAR PRIMARY AND SECONDARYFLOOD PEAK COMPUTATIONTABLE E-4 LIST OF HYDROLOGIC MODELSTABLE E-5 HYDROLOGIC MODEL SELECTION MATRIXWATER LEVEL COMPUTATIONS - OPEN WATERTABLE F-1 HYDRAULIC MODEL SELECTION MATRIXLIST OF FIGURESNATURAL Hazard POLICIES AND STANDARDSFIGURE B-1 FLOOD Hazard CRITERIA ZONES OF ONTARIOFIGURE B-2 ONE ZONE FLOODPLAIN CONCEPTFIGURE B-3 TWO-ZONE FLOODWAY-FLOOD FRINGE CONCEPTFIGURE B-4 SELECTION OF FLOOD STANDARDS AT CONFLUENCEOF LAKES.

6 RIVERS AND STREAMSFLOW COMPUTATION DATA REQUIREMENTSFIGURE D-1 DESIGN STORM SELECTIONFIGURE D-2 HURRICANE HAZEL STORM HYETOGRAPH ANDDIMENSIONLESS DISTRIBUTIONFIGURE D-3 HURRICANE HAZEL AREAL REDUCTIONFIGURE D-4 TIMMINS STORM HYETOGRAPH ANDDIMENSIONLESS DISTRIBUTIONFIGURE D-5A 24 HOUR DURATION MEAN ANNUALEXTREME RAINFALLFIGURE D-5B 24 HOUR RAINFALL STANDARD DEVIATIONFIGURE D-6 AREAL REDUCTION CURVESFIGURE D-712 HOUR STORM DISTRIBUTIONFIGURE D-81 HOUR URBAN DESIGN STORMFIGURE D-9 GENERALIZED PROBABLE MAXIMUMPRECIPITATION, ALL ONTARIOFIGURE D-10 100 YEAR SNOWPACK WATER EQUIVALENT MAPPINGWATER LEVEL COMPUTATIONS - ICE JAMSFIGURE G-1 SCHEMATIC ILLUSTRATION OF AN EQUILIBRIUM ICE JAMFIGURE G-2 DIMENSIONLESS DEPTH VERSUS DIMENSIONLESS ..DISCHARGE: River ICE JAMS IN EQUILIBRIUMFIGURE G-3 FREEZE UP AND BREAK UP STAGES VERSUSDISCHARGES; THAMES River AT THAMESVILLE ONTARIOFIGURE G-4 PROBABILITY DISTRIBUTION OF ANNUAL MAXIMUMICE-EFFECT STAGE AND OPEN WATER STAGEFIGURE G-5 COMPARISON OF SYNTHESIZED AND MEASURED ICERELATED STAGE PROBABILITY DISTRIBUTIONSFIGURE G-6 PROCEDURE FOR ESTIMATING THE FREQUENCY OFBREAK UP ICE JAM STAGES 20027 Technical Guide - River and Stream Systems: Flooding Hazard LimitOntario Ministry of Natural ResourcesAcknowledgementsThe Technical Guide, River and Stream Systems; Flooding Hazard Limit updates the 1986 Flood Plain Management inOntario Technical Guidelines, Ontario Ministry of Natural Resources (OMNR) and supports the Natural Hazard Policiesof the Provincial Policy Statement of the Planning Act.

7 Ivan Lorant of Dillon Consulting Ltd. updated the TechnicalGuide, River and Stream Systems; Flooding Hazard Limit , under the direction and guidance provided by a steeringcommittee of OMNR Water Resources staff of the Lands and Waters Branch, including:Ala Boyd (Chair)Pearl McKeenLes PatakyDon GreerJohn DingRon McGirrThe original 1986 Flood Plain Management in Ontario Technical Guidelines were prepared by the Conservation Au-thorities and Water Management Branch, Ministry of Natural Resources, under the supervision of Sardesai. Theprincipal writer was Ivan Lorant, , Chief Water Resources Engineer, Dillon Ltd. Guidance during prepara-tion of the guidelines was provided by a steering committee comprised of:Ivan Lorant (Chairman) Dillon SardesaiOntario Ministry of Natural DingOntario Ministry of Natural ResourcesH. WalshOntario Ministry of Natural ResourcesDr. A. SmithConservation AuthorityC. MatherConservation AuthorityR. WigleMacLaren & Associates the preparation of the guidelines and during subsequent review, input was also received from a number ofindividuals and agencies including provincial ministries, conservation authorities, Consulting Engineers of Ontario andvarious specialists, particularly:Dr.

8 E. WattDr. P. WisnerDr. T. DickinsonProctor & Redfern Ltd. (Mr. A, Perks)A. Robinson & Associates Ltd. (Mr. A. Robinson)Mr. S. BaltaosDr. L. GerardDr. N. KouwenMr. D. CalkinsParagon Engineering Ltd. (Mr. J. Gorrie) Kirchhefer Ltd. (Mr. S. Kirchhefer).All contributions, present and past are gratefully information concerning the Natural hazards Policies or the Technical Guide, River and Stream Systems; FloodingHazard Limit , please contact the Water Resources Section of the Lands and Waters Branch, Ministry of Natural Re-sources, in Peterborough, Ontario at (705) 755-1222. 20028 Technical Guide - River and Stream Systems: Flooding Hazard LimitOntario Ministry of Natural ResourcesA. PrefaceA new efficient and effective land use planning process wasintroduced in Ontario to replace the complex planning systemused in the past and to ensure the environmental, economicand social well-being of the people of 1997 Provincial Policy Statement issued under the au-thority of Section 3 of the Planning Act provides policy direc-tion on matters of Provincial interests related to land use plan-ning and development.

9 According to the Planning Act, plan-ning authorities shall have regard to policy statements is-sued under the Act. One important principle behind the Policystatement to achieve long-term economic prosperity, environ-mental health and social well-being is the reduction of publiccost and risk to Ontario s residents by directing developmentaway from areas where there is risk to public health or safetyor risk of property damage. Accordingly, the Province of On-tario adopted policies under Public Health and Safety policyareas addressing natural and human-made hazards . Part ofthe new approach empowers municipalities in protecting theenvironment and streamlining an ecosystem based plain studies form an important part of watershed man-agement and planning. Proper planning requires the balanc-ing of a wide range of public and private interests. Ecosystembased planning within a watershed or a sub-watershed, in-volves an up-front evaluation of numerous, and often compet-ing, land use and natural resources interests.

10 It provides ameans of examining and developing planning strategies thatbalance local as well as community-based needs. Throughecosystem based planning processes, environmental concernssuch as flood and erosion Hazard lands can be identified andincorporated into the land use planing Ministry of Natural Resources (MNR) through its re-focussed water management program will ensure that the pro-gram is effectively aligned with the Ministry s vision of sus-tainable development and its mission to achieve ecologicalsustainability. MNR objectives to achieve ecologicalsustainability include the continuation of Provincial programsfor the protection of life and property from Flooding and otherwater-related hazards , and the provision of direction and in-put through policy, information and science Provincial government s role in the planning and man-agement of flood risk areas is to protect society, including alllevels of government, from being forced to bear unreason-able social and economic burdens due to unwise Province sets minimum standards to ensure that theserisks and costs to society are reduced.