technical guidelines and requirements for approval …3.3.6 total diversion/relocation of the river...

DRAFT – FOR DISCUSSION PURPOSES ONLY

Ministry of Natural Resources

Ministère des richesses naturelles

Technical Guidelines and Requirements for Approval Under

The Lakes & Rivers Improvement Act

VOLUME TWO: WATER CROSSINGS, CHANNELIZATIONS, ENCLOSURES, PIPELINES, AND

CABLES

2010


NOTE:

The Ministry of Natural Resources is currently investigating ways to modernize provincial requirements for the construction and management of dams. The policies, standards and management practices contained within these draft technical guidelines represent the changes to provincial requirements currently being considered. The purpose of these guidelines is to provide dam owners, members of the public, and other interested parties an opportunity to provide feedback on the requirements being considered. The policies, standards and management practices contained within these draft technical guidelines are being shared for discussion purposes only and do not represent any commitment from the MNR to make any changes to existing requirements for the construction and management of dams.

2010

Table of Contents

VOLUME TWO: WATER CROSSINGS, CHANNELIZATION, ENCLOSURES, PIPELINES, AND CABLES

Chapter 1: General

1.1 Setting the Context Chapter 2: Water Crossings

2.1 General 2.2 Environmental Considerations: Water Crossings

2.2.1 Site Characteristics 2.2.2 Bridge Site Suitability 2.2.3 Culvert Site Suitability 2.2.4 Beaver Problems

2.3 Design Requirements for Water Crossings 2.3.1 Third Party Damage 2.3.2 Design Floods 2.3.3 Design Considerations

Chapter 3: Channelization Works

3.1 General 3.2 Channelization – Environmental Considerations

3.2.1 Impact on Fish Habitat 3.2.2 Trans-watershed Diversions 3.2.3 Bankfull Flow Determination 3.2.4 Vegetation 3.2.5 Natural Form Simulation 3.2.6 Fish Structures 3.2.7 Pond Stagnation 3.2.8 Fluvial Geomorphology

3.3 Channelization – Design Considerations 3.3.1 Natural Channel Design 3.3.2 Soils Investigation 3.3.3 Design Flood Criteria 3.3.4 Key Hydraulic Characteristics 3.3.5 Permissible Water Velocities 3.3.6 Total Diversion/Relocation of the River Channel 3.3.7 Where the New Channel is Shorter 3.3.8 Full Diversion of River Channel and Floodplain 3.3.9 Curvilinear Channel Alignment 3.3.10 Side Slope Stability 3.3.11 Erosion Control Structures 3.3.12 By-Pass Ponds

3.4 Enclosures, Pipelines, and Cables 3.4.1 Environmental Impacts of Enclosures 3.4.2 Design Considerations for Pipelines, Water Intakes, and Cables

Chapter 4: Erosion and Sediment Control

4.1 General 4.2 Ecological Considerations: Erosion and Sediment Control 4.3 Best Management Practices

4.3.1 Planning and Design 4.3.2 Construction Administration

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4.3.3 Stormwater Erosion and Sediment Control 4.3.4 Construction Work in Water

4.4 Erosion and Sediment Control Plans Chapter 5: Location Approval

5.1 General 5.2 Assessment of Upstream and Downstream Impacts within the Zone of

Influence 5.2.1 Private Land Tenure 5.2.2 Water Levels and Flows 5.2.3 Erosion and Sedimentation 5.2.4 Natural Amenities 5.2.5 Navigable Waters Protection Act (NWPA) 5.2.6 CA Generic Regulations 5.2.7 Aquatic Ecosystem 5.2.8 Wildlife and Wildlife Habitat 5.2.9 Species at Risk 5.2.10 Wetlands 5.2.11 Expiry of Location Approval 5.2.12 Water Crossings and Channelizations

Chapter 6: Plans and Specifications Approval

6.1 Water Crossings and Channelizations Works 6.2 Design Report

6.2.1 Hydrological Information 6.2.2 Hydraulic Information 6.2.3 Fluvial Geomorphology Information 6.2.4 Foundation Information 6.2.5 Design and Construction Information 6.2.6 Ecological Information (Aquatic and Terrestrial)

List of Tables Table 2-1: MNR Minimum Design Floods for Road Crossings Table 2-2: Permissible Channel Velocities Table 2-3: Summary Checklist of Information Requirements for Volume 2 Location Approval Table 2-4: Location Approval Information Required Table 2-5: Summary Checklist of Information Requirements for Volume 2 Plans and Specifications Approval Table 2-6: Hydrological Information Required Table 2-7: Hydraulic Information Required Table 2-8: Fluvial Geomorphology Information Required Table 2-9: Foundation Information Required Table 2-10: Design and Construction Information Required Table 2-11: Ecological Information Required Volume 2: References and Bibliography

VOLUME TWO: WATER CROSSINGS AND CHANNELIZATION WORKS, ENCLOSURES, PIPELINES AND CABLES

This Volume must be read in conjunction with Volume 1 which provides detailed information on implementing the Lakes and Rivers Improvement Act. This Volume provides information for guidance to applicants and direction to staff on Water Crossings and Channelization (which includes Enclosures, Pipelines and Cables) with respect to both Location Approval and Plans and Specifications approval. Volume 2 does not apply to dams. The requirements relating to dams are contained in Volume 3.

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CHAPTER 1.0: GENERAL

1.1 Setting the Context

This volume has been written to identify the requirements for channelization works and water crossings which are normally associated with land development, restoration projects, subdivision development; highway and road construction, rural drainage, etc., where the emphasis is on natural drainage of a watercourse and where it is desired to apply natural channel design. Volume 2 addresses the importance of having proper erosion and sediment controls in place. It discusses in detail, the requirements for assessing upstream and downstream impacts, as well as the responsibilities of the MNR and DFO regarding the impact of proposed works on aquatic habitat and resources. Additionally, this volume addresses the requirements for other types of works normally requiring some form of channelization work as part of their installation. They include enclosures of and covers on watercourses and installation of pipelines, cables, heat loops, water intakes and service cables, An understanding of natural stream system functions is necessary before designing channelizations and water crossings. A natural stream system should exhibit two key characteristics:

1. Physically, from a geomorphological standpoint, the stream system will be dynamically stable in that the river’s energy and the sediment load it can transport are directly related. It will exhibit changes in water yields and sediment loads; and

2. Biologically, the stream and valley system will be self-sustaining and self-

regulating. It will exhibit healthy ecological functions, manifested by productive vegetative communities in the valley and healthy aquatic and terrestrial communities supported by diverse habitats (Adaptive Management of Stream Corridors in Ontario, 2001)

Channelizations and water crossings have the ability to interfere with natural physical and biological processes and aquatic habitat. To mitigate or minimize the impacts of these activities on the natural system, natural channel design should be utilized. Natural channel management and design is the process by which new or reconstructed stream channels and their associated floodplain riparian systems are designed to be naturally functional, stable, healthy, productive, and sustainable. Natural channel systems develop from the interaction of climatic and physical conditions within a watershed and convey and store water and sediment. The design of such a system requires an understanding of the interactions of these processes. The management and design of natural channel systems advocates the following intent: to manage and design a natural channel system taking into account the ecological functions of the watercourse, where land use controls can maintain the quality of the ecosystem while allowing for compatible development (Adaptive Management of Stream Corridors in Ontario, 2001). 2010 1The changes in provincial policies, standards and practices contained within these draft technical guidelines are being presented for discussion purposes only and do not represent any commitment by government to change existing requirements for the construction and management of dams.


2010 The changes in provincial policies, standards and practices contained within these draft technical guidelines are being presented for discussion purposes only and do not represent any commitment by government to change existing requirements for the construction and management of dams.

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To understand and furthermore implement a proper natural channel design, this Volume promotes the principles of Adaptive Environmental Management (AEM) or Adaptive Management. The 2001 document entitled Adaptive Management of Stream Corridors in Ontario utilizes the AEM process in determining a proper approach to natural channel design. Further reference should be made to this document as it presents the key principles that direct MNR staff in their evaluation of channelization and/or water crossing projects. .


CHAPTER 2.0: WATER CROSSINGS

2.1 General

Approval granted under the LRIA does not include certification of structural integrity associated with the water crossing. Conditions to this effect will be stated in the Plans and Specifications letter of approval. MNR’s Environmental Guidelines for Access Roads and Water Crossings and the Crown Land Bridge Policy must be used in conjunction with the standards contained in these Guidelines. Where there may be a difference in standard, the higher level of standard will apply.

2.2 Environmental Considerations: Water Crossings

Water crossings may directly affect the aquatic ecosystem and adjacent terrestrial habitat. 2.2.1 Site Characteristics The selection of the type of structure depends on several factors including:

1. Site materials and conditions;

2. Geomorphic characteristics;

3. Ecological sensitivity;

4. Hydraulic characteristics;

5. Transportation requirements; and

6. Cost 2.2.2 Bridge Site Suitability Bridges, including corrugated steel arch spans, have several environmental advantages where they span the waterway avoiding obstructions to fish movement and in-water disturbances during construction. Site conditions suitable for bridge construction include the following:

1. Stream width allows for a single span;

2. Firm or hard foundations for abutments and footings;

3. Erosion-resistant soils; and

4. Effects of upstream backwater due to the constriction created by the crossing will be limited to a short length of river.

The bridge length or arch span should be selected to clear the bankfull channel. If piers are required to break a bridge span the number should be kept to a minimum, and ideally have no piers within the bankfull zone.

2010 3The changes in provincial policies, standards and practices contained within these draft technical guidelines are being presented for discussion purposes only and do not represent any commitment by government to change existing requirements for the construction and management of dams.


The bridge support span and clearance above flood water levels should be set to avoid possible ice and debris accumulations. 2.2.3 Culvert Site Suitability Site conditions suitable for round and pipe arch culvert(s) include:

1. Smaller watersheds, drainage basins;

2. Consideration of the impacts of the road or causeway in the floodplain (must address increased backwater effects);

3. Stream reaches with low sinuosity so that the straight culvert will fit the channel

a. channel modification, if approved, shall abide by the requirements for channelization; and

b. the maximum number of culverts at a water crossing should be three (3);

4. Normal water depth less than half the culvert diameter should allow fish passage at all times;

5. Design water velocities permit fish passage at normal and partial flood flows;

6. Streambed slope is less than 1.0 percent;

7. A streambed that:

a. Is free of boulders or bedrock

b. Provides a fine-grained substrate (gravel or finer) for embedment and foundation bedding; and

c. Will not settle unevenly when the road fill is placed over the culvert

8. Soil (existing or added) adjacent to the culvert is appropriate in quantity and quality for soil-steel culvert design; and

9. The water crossing site is regularly monitored and maintained

The DFO culvert / crossing design process entitled “Stream Simulation Design” should be referenced during the design process, particularly if fish habitat is to be impacted. Stream Simulation is a culvert design process that avoids flow constriction during normal conditions and attempts to replicate a natural stream channel within the proposed culvert. Typically these culverts are wider than the natural channel to allow for natural processes to occur within the culvert and also maintains sufficient water depth during low-flow conditions to maintain fish passage. The culvert is typically embedded into the substrate and native, natural bed material is utilized within the culvert to mimic a natural channel.

The design of a round and pipe arch culvert(s) should:

1. Be able to maintain proper sediment transport without excessive scour or deposition;

2. Not have smooth wall pipes in order to facilitate fish passage; and

3. Take the overall pipe length into account in order to facilitate fish passage. 2.2.4 Beaver Problems

2010 4Beaver dams can be a problem at bridge and culvert sites.

The changes in provincial policies, standards and practices contained within these draft technical guidelines are being presented for discussion purposes only and do not represent any commitment by government to change existing requirements for the construction and management of dams.


Upstream, at the inlet, beavers can take advantage of the constricted waterway and build a dam leading to blockage and increased water levels. The need for corrective action depends on the circumstances. A solution that has been used successfully in chronic problem areas is to construct a submerged discharge system which by-passes the beaver dam (The Beaver Handbook: A Guide to Understanding and Coping with Beaver Activity, 1995). 2.3 Design Requirements for Water Crossings The primary purpose of the review of water crossings is to ensure that there are no negative hydraulic and ecological impacts as a result of constructing these works. Negative impacts can be mitigated by installing a single structure (bridge or culvert) with a span that is wider than the natural channel width and if necessary, additional design flood capacity culverts or road overflow within the floodplain. 2.3.1 Third Party Damage Water crossings, including channels and drainage systems (conveyance and overland), must be designed so that there is no increase in damage beyond existing/natural conditions, caused to a third party during the design flood event. 2.3.2 Design Floods Criteria for assessment of the design flood magnitude for private bridges, culverts, and causeways must be in accordance with those of the Ministries of Transportation and Natural Resources. The following table 2-1 provides minimum design flood standards for water crossings.

Table 2-1 MNR Minimum Design Floods for Road Crossings

DESIGN FLOODS (see notes below)

ROAD CLASSIFICATION Total Span

(up to 6.0 m) Total Span (over 6.0 m)

Resource Access and Recreational Trails*

10 to 25 year 25 year

Temporary Detours* 1 to 5 year 1 to 10 year

Winter Roads (Removed Prior to Spring Melt)*

No requirement No requirement

Freeways and Urban Arterial Roads**

50 year 100 year

Rural Arterial and Collector Roads**

25 year 50 year



Local Road** 10 year 25 year

Source; MNR Technical Guide, River and Stream Systems: Flooding Hazard Limit May 2001 and MNR Crown Land Bridge Management Guidelines, February 2008 (*)

MTO Highway Drainage Design Standards, Standard WC-1 (bridges and culverts) January 2008 (**)

Notes

a) Design floods are normally based on existing runoff conditions, but may be based on a 20-year plan/development horizon or as outlined in official planning documents

i. If the road construction is likely to be upgraded or downgraded within 5 years of construction, the return period must be that for the future classification;

b) If a drainage facility designed to the criteria specified in the tables would increase flooding on developable land during a regional flood, the facility must be designed to the flooding hazard limit unless otherwise approved;

c) The total plan for bridges is measured from the centre of the abutment (end) support to the centre of abutment (end) support; and

d) The total span for corrugated culverts and arches is the structural /support span. For multiple culverts, add a minimum distance between each culvert of 1.0 m (for construction reasons) or culvert diameter(s), whichever is greatest.

Modifying Design Floods Normal design floods listed above are for average conditions only and should be modified, if necessary, as follows:

1. Circumstances that may require higher design standards include:

a) Structures with a span over 30 metres;

b) Impossibility of relief flow over the road under flood conditions which would prevent vehicle movement (freeway, arterial, collector road, and local road with no alternative access);

c) Increased potential for flood damages to property for floods up to the design flood;

d) Lack of reasonable alternative route;

e) Open-invert (half) culvert on scourable soil;

f) Maximum observed flood exceeds design flood;

g) Requirements of other regulatory agencies (e.g., DFO for aquatic habitat, Transport Canada for navigability); and

h) Other considerations (e.g., culverts under high fills).

2. Circumstances that may permit smaller design floods:

a) Unusually low traffic volume for class of road;

b) Future down-grading of road classification;



c) Summer use only (if relief flow over roadway is possible in larger floods); and

d) other considerations with supporting rationale.

3. Design to Regulatory Flood criteria is to be considered if, under Regulatory Flood conditions, a facility designed to normal criteria would:

a) Materially increase flood damage to buildings over that which would occur under existing conditions at the site, or

b) Create a backwater which would materially reduce the area of developable land upstream, provided that building development is expected within 20 years.

In all cases the probable benefit, tangible and intangible, should be commensurate with the added cost of the facility and should be discussed with the affected parties; e.g. municipalities and landowners.

2.3.3 Design Considerations While approval granted under LRIA does not include certification of structural integrity associated with the water crossing, the safety of the water crossing will be considered. There is an expectation that the project will be designed and installed to a reasonable structural standard. For roads under the jurisdiction of MTO, consult MTO design standards. Where engineering design is required, the plans and specifications must be sealed by a professional engineer. Where the support span is greater than 3m, the structure is deemed a bridge and subject to the current Canadian Highway Bridge Design Code CAN/CSA. MTO allows some exceptions (Exception to the Canadian Highway Bridge Design Code CAN/CSA-S6-00 for Ontario June 2002). The Crown Land Bridge Management Guidelines allows additional exceptions. Bridge design requires two engineers; a designer and a checker. Standard engineer designed components may use standard pre-manufactured items, such as panel bridges, portable bridges or corrugated metal pipes. Abutments, piers and piles must be designed to meet the Canadian Highway Bridge Design Code and the MTO Highway Drainage Design Standards. Generally, to minimize the size of a structure, relief flow over the roadway adjacent to the structure (except where the Regulatory Flood is the design flood) should be considered up to the maximum allowable backwater for existing conditions. Other measures should also be considered to reduce the backwater effects caused by a structure. Bridge Design The waterway opening must provide for the design flood plus clearance to the soffit, the underside of the main girders. The minimum clearance shall not be less than:

1. 1.0 m for freeways, arterial roads and collector roads; 2. 0.5 m for forest access roads; or

2010 73. 0.3 m for all other roads.



The road freeboard is measured from the water level or the design flood level to the edge of the pavement at the approaches to the bridge, and should not be less than 0.5 m. Culvert Design The waterway opening should limit the design flood level to the obvert/top of the culvert unless otherwise approved. The freeboard, to the crest of the road shoulder, shall not be less than 0.5 m. Where there are mixed uses for a crossing (e.g., pedestrian crossing) additional clearance standards may be required. Performance of culverts on fish migration routes shall be checked to ensure appropriate fish passage. Note: The nominal waterway span for corrugated culverts and arches is the measured horizontal maximum distance from wall to wall; inside of corrugation to inside of corrugation. However, the structural/support span for corrugated steel structures is the measured horizontal distance from centre of corrugation to centre of corrugation. Culvert Installation Practices Good practices include:

1. Field surveys are required to obtain data for design purposes such as topography, ecological and soil conditions for the channel and floodplain. Survey at the crossing site and, as required, upstream and downstream;

2. Install culverts level (0%) to a maximum 1.0 percent slope;

3. Embed the culvert at least 10 percent of its diameter below the streambed elevation with at least a 20 cm depth of water;

a. The cross-sectional area (sq. m.) above the expected substrate level must be equal to or larger than the culvert size (sq. m.) required to pass the design flood while limiting the flood level to the top of the obvert pipe;

b. Placement of material to simulate the natural substrate is required. On smaller culverts, filling by natural bed-load movement may be the only practical method.

4. Install the culvert(s) according to the manufacturer’s recommendations;

a. Place soil around culverts carefully and compact in thin layers, on each side so as not to float or distort the pipe shape.

b. Prevent piping along the outside of the pipe by installing seepage collars or cut-off walls. Headwalls or other impermeable material (e.g. clay) may also be used at the inlet and outlet to prevent piping.

5. The appropriate culvert pipe material should be selected based on site conditions and the expected life of the culvert. Site conditions include the chemical characteristics of the water and backfill soil and height of fill.

6. Buckling in of thin wall culvert pipes under buoyant conditions (uplift) can be a problem. Appropriate counter-measures include anchoring to headwalls,




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covering culvert ends with embankment slope fill material, as well as ensuring adequate flow capacity through regular maintenance to clear debris; and

7. On wide shallow rivers or wide floodplains, avoid concentrating design flood flows within the centre portion of the channel. Provide additional culvert(s) or road overflow in the floodplain to pass flood flows exceeding the design flow.

Soil Erosion and Scour The alignment of bridges or culverts should not cause currents to erode road or channel embankments. Headwalls and aprons are used to prevent erosion at the entrance and exit. Soil for causeways built in the floodplain should remain stable in flood water conditions. Riprap or similar material should be placed up to the design flood levels or bridge or culvert capacity.


CHAPTER 3.0: CHANNELIZATION 3.1 General Applicants proposing channelization works are required to assess both the existing conditions as well as the impact of the proposed work. Channels must be designed and constructed using natural channel design principles. 3.2 Channelizations - Environmental Considerations A range of mitigation measures are available to reduce the potential adverse environmental impacts of a channelization project. The following is a list of possible mitigation measures that must be considered and assessed for channelization projects:

3.2.1 Impact on Fish Habitat Fish habitat loss is a prime concern with channelization works and their associated artificial channel features, such as drop structures, which may impede fish movement. This will be addressed through review with DFO. MNR’s Fisheries Management Objectives need to be identified as early as possible in the LRIA review process and provided to DFO so that these can be taken into account during DFO’s review. 3.2.2 Trans-Watershed Diversions A diversion from one watershed to another can have serious implications and should not be contemplated without an assessment of environmental impacts. 3.2.3 Bankfull Flow Determination A river system depends on the main channel to carry the bankfull flow (often estimated to be from 1:1.1 to 1:2.33 year return frequency) and the flood plain to convey the larger portion of a flood event (up to the flooding hazard limit). 3.2.4 Vegetation Channels in their natural form depend on vegetation to protect banks. Hardening of channels with walls or revetments should be limited to situations where they are required to protect existing development from natural hazards. Plantings and/or bioengineering techniques should be used wherever possible. In-stream ponds and by-pass ponds cause warming and evaporation losses. These can be reduced by shade plantings. 3.2.5 Natural Form Simulation



Channeled watercourses that are designed to simulate natural forms, such as, pool-riffle or step-pool formations, will provide enhanced ecological benefits. 3.2.6 Fish Structures Channelization may be improved by adding fish structures such as deflectors and root wads and other forms of bioengineering techniques that provide local bank and overhanging structure.

3.2.7 Pond Stagnation Ponds, or parts of ponds, may become stagnant and form algae. Ponds should be designed to promote circulation and avoid stagnation. Refer to the Temperate Wetland Restoration Guideline for further information and best practices.

3.2.8 Fluvial Geomorphology Fluvial geomorphology is the study of physical processes in stream systems and is a key component of any examination of creek, stream or river form and function and even more important in natural channel design. Fluvial geomorphology examines sediment transport, hydrology, contour, geometry and reach characteristics. The practical application of fluvial geomorphology is “natural channel design” where science is applied to the practice of restoring or rehabilitating channels. A key concept in fluvial geomorphology is “dynamically stable” or the balance of water and sediment transport in the channel over time. Over short periods of time there is movement of sediment in bars and riffles but over a long period of time, the channel appears to be the same. Any alteration of the stream will result in an adjustment of the sediment regime. The study of the stream will allow us to predict the possible extent of the adjustment and its future pattern. Channel form is essentially determined by stream energy (related to flow and slope) and the extent to which streams dissipate that energy. The energy of the water/sediment flow acts against the banks and bed of the channel (as determined by the local geology) and the result of the interaction is the channel shape. Interactions in certain conditions can create pool-riffles in a meandering system while in steeper terrain, alternating step-pool formations are created. The change in any of the various geomorphic parameters (flow, velocity, shear stress, width, depth, slope and contour) will result in the change in other parameters. This is simply shown by Lane’s Balance Equation – Equation 2-3 where: Equation 2-3: Lane’s Balance Equation Qsediment x D50 α Qwater x Slope Qsediment = sediment discharge D50 = sediment particle size Qwater = streamflow



Slope = the grade of a stream reach In normal streams the relationship is in balance, while in eroding or depositional stream systems, it is not in balance. The stream valley is composed of four distinct regions that must all be considered in a natural channel design. The zones are the base flow zone, bankfull zone, riparian zone and finally the floodplain zone. While all these aspects are important to a natural channel design, the bankfull flow is the most relevant for channel formation. From a LRIA perspective, particularly with respect to channelization and water crossings, a fluvial assessment should be provided which may include (but certainly not be limited to) the following:

1. Determine the level of investigation and detail required (observation, measurement, analysis and/or prediction);

2. A historic review of aerial photography over a wide range of years to determine historic patterns, possible trends and rates of erosion;

3. Dimension: Cross sectional characteristics; 4. Pattern: Contour characteristics can be determined from mapping or aerial

photography; 5. Profile: Longitudinal profile of the stream showing pools, riffles, glides, runs,

bankfull and water surfaces; 6. Sediment characteristics based on grab sampling and/or pebble counts to

characterize the system roughness and sediment transport potential; 7. Application of a rapid geomorphic assessment technique; 8. Determination of the role of other influences on the system (groundwater, ice,

temperature, and riparian inter-relationships and pathways); 9. Channel thresholds; 10. System hydrology and hydraulics; 11. Comparisons to hydraulic geometry relationships (if available); 12. Stream classification (for the purposes of communication); 13. Assessment of sediment transport rates and/or boundary shear stress conditions; 14. Design alternatives; and 15. Final design details and reporting.

Based on the fluvial assessment, the following general constraints should be observed:

1. Maintain the sediment transport potential of the existing channel; 2. Maintain the Dimension, Patterns and Profile that corresponds to a stable

system; 3. Maintain the riparian pathways; and, 4. Maintain fish habitat.

Other aspects related to proper channel design and mitigation have been addressed in other sections (e.g.: erosion and sediment control, flood capacity, aquatic biology, etc). 3.3 Channelization – Design Considerations



Unless legal authority is obtained, channelization (including diversion channels) must be mitigated from what occurs under natural channel conditions with respect to:

1. Flood damage 2. Flood frequency 3. Erosion rates and/or frequency along both sides, upstream or downstream of the

channel 4. Not lowering river water levels detrimentally (i.e. affecting riparian rights or

aquatic ecosystems) In recognition of the above environmental considerations, applicants and/or their agents should be guided by the following design considerations when contemplating channelization works: 3.3.1 Natural Channel Design Wherever possible, natural channel design should be the approach of choice. Natural channel design promotes the stability of natural systems and advocates the continuous movement of bedload material and biological plant growth (both above and below ground) to provide resistance to bank erosion. More information on natural channel design may be found in the following two documents, available from the Ministry of Natural Resources through the Trent University Watershed Science Centre.

1. MNR’s Adaptive Management of Stream Corridors in Ontario. (2001) 2. Natural Hazards Technical Guideline, Ministry of Natural Resources (2001)

3.3.2 Soils Investigation Where channel realignment is proposed, a soils investigation may be required in order to understand the native soils that will be encountered and how they will behave. As a general rule, channel banks should be stable under saturated conditions (usually not steeper than 2 horizontal to 1 vertical). Depending on whether a natural channel design is to be implemented, the bed and the banks should be capable of resisting scour under extreme flow conditions for an in-regime channel while the bed and banks may be subject to limited movement in a mobile bed, dynamically stable stream. If necessary, revetments should be placed on safe slopes (2 horizontal to 1 vertical or flatter) and filter materials must be placed under revetments to allow for drainage, and to prevent finer soils from escaping. 3.3.3 Design Flood Criteria Channelization (including diversions, retaining walls or revetments) which will alter the storage or discharge characteristics of the flood plain or a river may be designed using a design flood ranging from the 25 year return frequency event to the Regional flood. The channel capacity may be designed for less than the 25 year flood (e.g. 10, 5 or 2 year flood), but the combined capacity of the channel and flood plain must meet the design flood criteria for Very Low Hazard Potential Classification (HPC) dams in the IDF table located in Volume 3.



A design flood above the regulatory flood and up to the Probable Maximum Flood (PMF) is not normally used in channel design except for special cases. Bankfull discharge of a river natural flow channel usually corresponds to the 1:1.1 year to the 1:2 year return period depending upon the stream type and basin conditions. Urban systems will have comparatively lower bankfull discharge return periods as the frequency of flooding is significantly higher with “improved” local drainage systems. 3.3.4 Key Hydraulic Characteristics The conveyance and storage capacity of the channelized reach must be identical to that of the original watercourse. The hydraulic characteristics of a natural river channel and its floodplain must be maintained despite any diversion or channelization of the river. This applies to all diversions and channelization works, regardless of length or size. The intent is to prevent a cumulative effect of increased flood levels and/or flood frequency and increased erosion rates and/or erosion frequency in the river as a result of the addition of new diversion or channelization works. To ensure that the conveyance and storage characteristics of the channel reach are identical to that of the original watercourse, the hydraulic characteristics of the natural watercourse must remain the same in the proposed channel.

In submitting channelization works for approval, applicants and/or their agents must address the following key hydraulic characteristics:

Travel Time: The travel time of peak flows in a river system can change the volume and depth of water at given locations, and therefore the same time-of-concentration of storm hydrographs in the watershed must be maintained. Stage Discharge The stage-discharge curve in the natural river channel and its flood plain up to the regulatory flood and the corresponding proposed flood levels in the altered channel must not be greater than existing conditions. Stage Storage The stage-storage curve of the natural river channel and its flood plain must be compared to the proposed channel and resulting flood plain in 30 cm channel elevation increments from channel bed up to the design flood level to ensure that the flood plain storage will not be decreased at any water level. Provided it is supported by a fluvial geomorphological assessment, the ‘Key Hydraulic Characteristics’ discussed above, need not be applied under the following circumstances: Cumulative Impacts



The objectives of the key hydraulic characteristics are met if the cumulative impacts of all future works in the watershed are quantified through sub-watershed studies and are considered insignificant. Downstream Impacts There are no downstream impacts (i.e., channel outlets into a lake and/or reservoir and the flow is therefore sufficiently dissipated.) Discharge-Storage Relationship The discharge-storage relationship of the watercourse is maintained on an incremental basis for all floods (from the 2 year return flood to the flooding hazard limit as defined in the Provincial Policy Statement). Routing Calculation Results Routing calculations that demonstrate that there would be no increase in downstream peak flows and total storage has been maintained or increased. 3.3.5 Permissible Water Velocities In instances where a natural channel design is not required, the permissible water velocities shall not be greater than those listed in the following Table 2-2:



Table 2-2: Permissible Channel Velocities

Maximum Permissible Velocity (m/s)

Original Material Excavated for Channel

Clear Water, No Detritus

Water TransportingColloidal Silts

Water Transporting Non-colloidal Silt, Sands, Gravel, or Rock Fragments

Fine sand (non-colloidal) 0.46 0.76 0.46

Sandy loam (non-colloidal) 0.53 0.76 0.61

Silt loam (non-colloidal) 0.61 0.91 0.61

Alluvial silts (non-colloidal) 0.61 1.07 0.61

Ordinary firm loam 0.76 1.07 0.69

Volcanic ash 0.76 1.07 0.61

Fine gravel 0.76 1.52 1.14

Stiff clay (very colloidal) 1.14 1.52 0.91

Graded, loam to cobbles (non-colloidal)

1.14 1.52 1.52

Alluvial silts (colloidal) 1.14 1.52 0.91

Graded silt to cobbles (colloidal) 1.22 1.68 1.52

Coarse gravel (non-colloidal) 1.22 1.83 1.98

Cobbles and shingles 1.52 1.68 1.98

Shales and hardpans 1.83 1.83 1.52

Note: The above velocities are for straight channels. Multiply velocities by 0.95 for slightly sinuous channels, 0.9 for moderately sinuous channels, and 0.85 for highly sinuous channels. 3.3.6 Partial Diversion/Relocation of the River Channel If only the river channel and not the floodplain is to be totally diverted (relocated), the new channel must have a length, slope, cross-sectional area, and roughness coefficient sufficient to maintain the three key hydraulic characteristics and to maintain proper geomorphic characteristics (e.g. sediment transport). Land ownership will need to be addressed for diversions or relocated channels. 3.3.7 Where the New Channel is Shorter If the new channel must be shorter than the existing channel being replaced, then it must have a larger cross-sectional area to maintain the same channel storage volume and a lower water velocity to maintain the same travel time. However, this may impair proper fluvial functioning and a higher priority must be given to maintaining a natural rate of sediment transport through the system by implementing low flow and bankfull flood flow



channel cross section characteristics. Increase travel times may also be addressed by other mitigation measures such as creating on-site and off-site runoff storage. 3.3.8 Full Diversion of River Channel and Floodplain If both the river channel and the flood plain are to be diverted or altered, there must be no increase or change in:

1. The design peak flood level (as compared to the existing channel and flood plain);

2. The stage-storage relationship in 30 cm elevation increments (as compared to the existing channel and floodplain); or

3. Floodwater detention areas in the watershed above or immediately below the site.

3.3.9 Curvilinear Channel Alignment Streams are products of local geology and climate. Further independent controls are valley slope, channel discharge, sediment loadings, and the bed and bank material. Each system is unique given the unique set of parameters for each system. All these parameters influence the available energy that a stream has, and also the channel morphology on a reach and cross-section scale. In order to adequately dissipate its energy, a stream will seek an alignment that is curvilinear wherever possible to reduce flow velocities and maintain natural conditions. However, the contour characteristics of any channel must be determined in a fluvial geomorphological assessment of historic and current aerial photography and/or available mapping and site inspections. 3.3.10 Side Slope Stability Side slopes of channels shall be constructed with slopes that will remain stable under saturated conditions. Side slopes should be no steeper than one vertical to two horizontal or flatter for most soils. The river bed and embankments should be able to resist scour under extreme events. Filter materials must be placed under revetments to allow drainage and to prevent the removal of fine soils. If an artificial channel is proposed where velocities at flows up to and including design flood flow are above the upper limit permitted, means (such as, weirs or drop structures) must be provided to dissipate energy and reduce water velocity to the permissible level with due consideration for the aquatic ecosystem. If a natural channel design with mobile-bed sediment characteristics is proposed, the bed and banks will be designed for allowing limited movement while maintaining dynamic stability. The amount of vegetation along a stream bank strongly affects the bank stability. While proper slopes will permit the growth of vegetation, vegetation itself will ultimately determine slope stability. As a result, erosion protection using bio-engineering techniques or riprap or equivalent material should be placed on side slopes of diversion channels at bends and other locations where flow velocity will be at or will exceed the maximum permissible velocity to prevent erosion and shall extend from the toe of the



slope to the high-water level. Bioengineering, and in particular the use of plant material immediately along the stream bank, also has other ecological and water quality benefits. Diversion banks (side slopes) above the normal water surface shall be protected from erosion from surface run-off by placement of sod or by the planting of grass using a bio-engineering fiber mat or other approved means of limiting erosion. 3.3.11 Erosion Control Structures While it is preferred that erosion control structures are not placed within stream systems (given their impact on physical processes), when these structures must be included in a design, the following design requirements are to be considered: Soil Pressure & Weight Design of the structures should take into account active and passive soil pressures and the unit weights of the soil. The backfill material must be free-draining and relief drains must be provided in the structure if the unit weights are based on dry conditions. Rigid Structures Rigid structures must be founded below the frost line and set back from the channel bed and located on a stable slope. Scour Velocities Scour velocities must be determined and measures implemented to prevent undermining. Erosion The alignment of embankments and retaining walls should not cause currents to impinge on and erode unprotected banks. Embankments The foundation soils should be capable of supporting the weight of the embankment. Embankment materials should consist of clean fill, free of deleterious materials. Compensating excavations should be carried out to maintain the flow storage characteristics. Embankment Slopes Slopes for earth embankments should be no steeper than 3 Horizontal: 1 Vertical. Rock-fill embankments can have steeper slopes, typically 1.5 Horizontal:1 Vertical. Like revetments, stable slopes typically require filter material to separate the large and small particles, allow drainage at various water levels, and prevent the escape of fine soils. Granular(s) or synthetic (geotextile) materials can be used between riprap and native soil. 3.3.12 By-Pass Ponds On-Stream Ponds Irrespective of size, on-stream ponds on cold water streams are generally discouraged because of increased evaporation losses, thermal, and sedimentation impacts on the aquatic system.



By-pass Ponds Ponds that are located parallel to the main channel with an inlet and outlet to the stream constitutes a type of diversion called by-pass ponds. Frequently, the inlet and outlet connections are made with pipes. Generally the project should be designed so that no more than 1/3 of the natural stream flow can be diverted through the by-pass pond at any time. Embankments must be safe from over-topping and anti-seepage collars should be installed on pipes through embankments. Where embankments are added to by-pass ponds to increase the water depth above the natural water level in the watercourse, they become dams and they will be subject to the requirements outlined in Volume 3. The following Design Considerations should be taken into account in by-pass pond design: Structural Integrity Structural integrity of dams or dikes (embankments) between the pond and stream should be assessed using similar procedures as for dams located in Volume 3. Shut Off Valve or Gate to Inlet The inlet to the pond must be equipped with a shut-off valve or gate. Coldwater Stream Considerations If located on a coldwater stream, the outflow must be through a bottom draw-off with entry to the draw-off at a minimum pond depth of 3 metres. Summer Inlet Gate Closure if Water Temperature Increases Due to By-pass Pond If located in the headwater area of a coldwater stream, the surface area of the pond should not exceed 0.4 hectares or 1 acre. Approval shall be subject to the operating condition that the inlet gate be closed during summer periods if the water temperature of a coldwater (trout) stream downstream of the pond outlet is increased due to the by-pass pond. 3.4. Enclosures, Pipelines and Cables Enclosures are constructed to cover streams, usually to allow development to take place on the surface. Pipes installed on small streams provide an example of a typical enclosure. The criteria for water crossings and other channelization works should be used for the review of enclosures. 3.4.1 Environmental Impacts of Enclosures




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The hydraulic and environmental effects of enclosures are similar, but likely more severe than those associated with culverts and channelization. 3.4.2 Design Considerations for Pipelines, Water Intakes and Cables Approval under LRIA is required where any streambed or bank is excavated to install pipelines. The review of an excavation of the streambed to install pipelines and/or cables is to be treated identical to a channelization project. Sedimentation & Erosion Potential Pipeline and cable projects usually involve clearing and trenching of the banks and areas adjacent to the stream potentially leading to increased sedimentation and possible increased backwater. Erosion and Sediment Control measures should be applied. Backfilling Excavation of the bed or bank for a pipeline or cable is required to be backfilled with acceptable material to suit existing or natural channel conditions.


CHAPTER 4.0: EROSION AND SEDIMENT CONTROL 4.1 General Erosion and sedimentation can result from in-water construction of water crossings and channelization works (Instream Sediment Control Techniques Field Implementation Manual, 1996). Erosion is a two-part process. Soil particles first become loose and are then transported by flowing water or wind action. Erosion rates are affected by precipitation (duration and force of loosening agents), soil characteristics (susceptibility to erosion), topography (slope and force of erosion and transporting agent), and ground cover (vegetation). Erosion control treatments must address at least one of these factors to be effective 4.2 Ecological Considerations: Erosion and Sediment Control From an ecological perspective, excessive sediment introduced into streams and rivers from construction sites can be harmful to channel processes and stability as well as to fish and to the aquatic ecosystem. Large increases of sediment into streams, over and above ambient load can result in channel infilling, leading to accelerated bank erosion, widening, and further secondary loadings of additional sediment into the channel. These all result in impacts on channel stability and the aquatic ecosystem. At certain times, fish are more vulnerable to harm from sediment than at other times. The risk to fish can be reduced considerably by scheduling construction outside the fish spawning, incubation, and fry emergence times. This occurs at different times of the year for different fish species. Please refer to section 5.2.8 for direction on timing windows and fish habitat. 4.3 Best Management Practices Potential long-term impacts must be eliminated through site stabilization. Although short-term impacts may be unavoidable, most streams will recover as high (greater than or equal to full bank) flows flush the sediment downstream to natural settling areas (ponds or lakes). The adverse impacts of erosion and sedimentation can be avoided by good planning and control. Erosion and sedimentation must be effectively controlled. Effective control measures are developed during planning, and design stages and implemented during construction, and monitoring of the project. This means that the constructor must minimize the impact by reasonable use of erosion and sediment control measures. All projects approved under the LRIA must be built so that any sediment introduced during construction will be reduced to the lowest practical amount. This is achieved by using Best Management Practices (BMPs), as discussed in the section that follows. The selection of BMPs must suit the particular construction site.



Control of erosion and sedimentation requires a risk management approach. Some key questions to be considered include the following:

1. What is the worst that can happen?

2. What are the consequences?

3. What is the likelihood that it will happen?

The best management practices provided below should achieve satisfactory erosion and sediment control. These practices are effective, practical, and can be implemented at relatively low cost.

Implementation of these Best Management Practices does not eliminate the need to comply with the Fisheries Act.

4.3.1 Planning and Design

Sediment Control Measures Include sediment control measures in all project stages, including the conceptual design. In addition, the need for sediment control measures should be considered when evaluating alternatives, e.g., a long, single-span bridge that requires no work in water may be preferred over a multiple span. Terrain Fit the water-crossing approaches to the terrain to reduce cut and fill grading. Proactively Identify Issues Identify construction methods and erosion and sediment control issues that may arise. Manage Streamflow Consider how streamflow will be managed during construction. For example, when placing a small culvert, will the pipe be installed in flowing water or will a temporary by-pass channel be used? If it is a complex project or if there is a high risk to the aquatic ecosystem, the sub-contractors should be provided with draft work staging sequences and include erosion and sediment control details at each stage. Provide permanent, end-of-construction erosion control techniques to ensure that the area will be stable before and after equipment moves off site. Minimize Soil Exposure Grading and construction activities should be scheduled to minimize the duration of soil exposure. Winter is not a good time to do construction near water. If work cannot be scheduled at another time, special care must be taken to ensure that erosion and sediment will be under control by spring. Vegetated Buffer Zones A vegetated buffer zone (i.e. trees, shrubs, and grasses) should be retained around the perimeter of water courses to provide shading to help minimize summer water temperature increases in the pond, reduce erosion, and subsequent transportation of



nutrients into the water and increased subsurface nutrient uptake. Further, removal of vegetative cover should be minimized in order to:

1. Reduce the amount of replanting of vegetative cover following construction; and 2. Reduce construction and maintenance costs.

4.3.2 Construction Administration Assign Accountability Assign clear accountability for sediment control to named individuals (e.g., planning, monitoring, and response to problems). Use Professionals Use experienced contractors for work in water. Encourage the contractor’s input to erosion and sediment control planning. Conduct Training Conduct training for all workers to review planned erosion and sediment control measures, including an explanation of why these are important. Plan for Contingencies Have contingency plans and extra materials on site or readily available on short notice in case of heavy rainfall. Wet Weather Hiatus Delay work in wet weather, especially if the creek or river is at flood stage when work in water is scheduled. Work in a continuous manner and install erosion controls as early as possible. Regular Inspections Use regular inspection and maintenance procedures to ensure that erosion and sediment control measures are working. 4.3.3 Stormwater Erosion and Sediment Control Effective Mitigation Techniques Select mitigation techniques that will be effective for the particular type of erosion to occur (e.g. splash, sheet, rill, gully, channel). Divert flow away from exposed soil by using diversion berms and/or interceptor ditches. Erosion Standards Slow down flowing water to reduce erosion and allow sediment to settle out close to its source through the use of such techniques as silt fences, rock check dams, and multiple silt fences. For larger drainage areas, direct the flow into channels that are protected from erosion. Channels must be adequately sized and include lining, check dams, transition sections, and energy dissipaters as necessary. Also, detention ponds should be considered to settle out soil particles before entering the channels.



Use coarse granular soil or other erosion-resistant material for fill placements near water. Grade disturbed soils to a stable angle then apply a seed mixture that is appropriate to the work site area and mulch to encourage early re-vegetation. Vegetation will provide long-term, self-perpetuating, and flexible erosion control and, therefore, it is the key component in site stabilization. Bioengineering techniques should be used for stream bank stabilization where possible. Install soil coverings if immediate erosion control is required (i.e., by using erosion blankets, woody debris mulch, riprap, etc.). 4.3.4 Construction Work in Water Timely Completion In-water works should be done quickly and in a sustained manner to minimize the amount of in-water time. When work in water is expected to last more than a day or two, flowing water should be separated from the work areas. Techniques include silt fences fastened to posts, floating silt curtains, temporary by-pass channels, damming and pumping flow around the work site, and erosion-resistant cofferdams (i.e., steel-sheet pile or similar). Minimize Sediment Transport Choose materials which are placed in water to minimize sediment transported downstream. It is a good practice to use materials that are coarser than the existing streambed material. Materials for restoring stream substrate should be stable under flood flows and should be suitable for fish. Clean diverted, water-carrying sediments using a settling basin or filter bag prior to discharging back into the stream. 4.4 Erosion and Sediment Control Plans

Erosion and Sediment Control Plans help to identify potential erosion and sedimentation issues as well as actions that can be taken to minimize impacts. In this way, these Plans are effective tools for ensuring that sedimentation and its effects, are controlled.

Erosion and Sediment Control Plans are used to:

1. Assist in establishing the construction sequence,

2. Identify operations that could cause sediment to enter the water body, and

3. Identify measures that will be taken to control erosion and sediment.

The benefits of using sediment control plans include the following:




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1. It encourages a proactive approach and allows potential problem areas to be identified along with mitigation measures;

2. It promotes more flexibility with respect to the timing of work (i.e., spawning or incubation period);

3. It provides a formal mechanism to communicate clear instructions to on-site workers and it defines performance criteria that will be used for evaluation and monitoring purposes; and

4. It provides owners and regulators with the assurance that administrative controls are in place to keep environmental impacts within expected levels.


CHAPTER 5.0: LOCATION APPROVAL

5.1 General

Applications for approval under LRIA are reviewed from a number of perspectives in keeping with the purposes of the Act. See Volume 1 for more information. This Chapter focuses on Location Approval which includes assessing the upstream and downstream impacts of proposed works within the zone of influence. Proposed works can have impacts on other uses and users, and as such these impacts must be taken into account by the MNR in the submission review process. Of particular interest are the rights of riparian owners whose interests and properties can be adversely affected. Once an application for a water crossing or channelization work has been submitted, a scoping meeting may be requested by the MNR office as outlined in Volume 1.

Table 2-3 Summary Checklist of Information Required for Volume 2 Location Approval

Types of Information Requirements Types of Work 1 Application form information (already provided) All Additional Information 2 Legal Instruments – right to flood All 3 Statements of authorization from affected riparian owners All 4 Watershed maps, Official Plans – existing and future (20 yr) land use All 5 Ecological information (aquatic and terrestrial) All

6 Water quality information including thermal impacts, oxygen content Ponds 7 Natural channel design, including meandering patterns, pool and

riffle patterns, sediment load Channelizations

8 Natural amenities present at the site All 9 Plans and specifications application date All

5.2 Assessment of Upstream and Downstream Impacts within the Zone of Influence

Staff should take the following into consideration when reviewing the application:

1. Crown land ownership

2. Private land ownership

3. Riparian owners rights

4. Public rights and interests

5. Affected landowners

6. Water levels and flows

7. On-site resources that may have to be cleared prior to construction

8. The presence of natural on-site amenities

9. Whether the waterway is a navigable waterway by definition

10. Cultural values (archaeological, grave sites, etc.)



11. Ecological integrity; and

12. Construction timing windows Applications Affecting Provincial and Municipal Highways and Roads As appropriate, the local regional office of the Ministry of Transportation or the Municipality shall be advised by the applicant and given the opportunity to comment on applications for works if they are to be located near publicly owned roadway as follows:

1. Works to be located upstream or downstream that will have a detrimental effect on a public roadways, e.g., will cause erosion or flooding to a roadway structure or embankment due to the location near the roadway; and

2. Applications for possible flooding and erosion effects on public bridges and culverts in order to check if the proposed location for the works conflicts with the location for any planned new roadways.

5.2.1 Private Land Tenure All water crossings and channelization works must be located on lands owned by the applicant, or on private lands not owned by the applicant for which the applicant has acquired the necessary rights to either access, occupy or temporarily flood the site. This requirement applies to water crossings and approach roads including both banks and the bed of the stream and the full extent of any channelization works A water crossing or channelization shall not cause permanent or periodic flooding or erosion on private land located upstream or downstream as a result of the location, design, construction, state of repair, and/or operation of the proposed works where the applicant does not have the legal authority to flood or erode above the level that would occur under preconstruction conditions. 5.2.2 Water Levels and Flows Applications are examined in terms of the potential impact to water levels and flows resulting from the proposed works. For the most part, the two critical concerns with Location Approval are:

1. The increased flows that result from increased conveyance capacity on the downstream area; and

2. The increase in water levels that result from reduced conveyance capacity on the upstream area.

Any changes to the natural flow capacity and channel storage characteristics of the stream can cause changes in downstream or upstream flow patterns. Reductions in channel storage can cause changes to the timing of flood peaks (delayed or advanced) and cause increased downstream flows. There is a need to understand the impacts in downstream areas of the watershed for all works that modify the natural channel storage and flow characteristics. A reduction in channel capacity can increase flood levels upstream.



This may require detailed analysis or modifications to the works to manage flow and channel storage changes. If it can be readily seen that a reduction in channel storage will not aggravate downstream flooding, a detailed analysis is not required. An example of this is a large receiving body of water immediately below the works where the impacts of increased flow would be insignificant. Provincial Policy Statement The PPS, 2005 directs development away from natural hazard lands and sites where there is an unacceptable risk to public health or safety or of property damage. Development and site alteration is not permitted within the dynamic beach hazard, defined portions of the one hundred year flood level along connecting channels, areas that would be inaccessible during times of flooding, erosion and/or dynamic hazards (unless it has been demonstrated that the site can have safe access) and within floodways. Despite the above-described prohibition, development and site alteration in certain areas identified above may be permitted in exceptional situations where a Special Policy Area has been approved by the Ministers of MMAH and MNR or where the development is limited to uses which must be located within a floodway (e.g. flood control works). The PPS, 2005 identifies uses that are not permitted to locate in hazardous lands and sites including various institutional uses and essential emergency services. Uses associated with the disposal, manufacture, treatment or storage of hazardous substances are not permitted in these areas. Where the two zone concept for flood plains is applied, development and site alteration may be permitted in the flood fringe area, subject to appropriate floodproofing. Subject to other criteria, development and site alteration may be permitted in parts of hazardous lands and sites where the effects and risk to public safety are minor so as to be managed or mitigated in accordance with provincial standards and where the following is achieved:

1. Development and site alteration meets floodproofing, protection works and access standards;

2. Vehicles and people have a way of safely entering and exiting the area during times of flooding, erosion and other emergencies;

3. New hazards are not created and existing hazards are not aggravated; and 4. No adverse environmental impacts will result.

Flood Level Water crossings with bridges and culverts often create a backwater during floods. The depth of backwater depends on the design standard for the culvert or bridge and the possibility of providing relief flow over the roadway during overtopping of high flows. The minimum standards for water crossings are shown in Chapter 2 and are also identified in the report Adaptive Management of Stream Corridors in Ontario.



Alterations in the timing and magnitude of flood flows should be considered in assessing the flow regime because they can cause bank erosion, increased sedimentation, modifications of pool riffle sequences and changes to the width-to-depth ratio of the stream. Such alterations are brought about by land use changes and the cumulative effect of instream works such as water crossings and channelizations. For this reason, individual project concerns should be addressed as well as the cumulative impacts of other similar projects on the same river system. Lakes Flow in lakes is generally slower than rivers, and changes in flow and water level are usually more gradual. Currents and water level fluctuations in lakes are influenced by wind as well as flow moving through the lake. Flow causes the movement of suspended and bed-load sediments. These movements are limited in lakes. In lakes with large surfaces, the main movement of sediment is due to wind and wave action. Sediments are produced by wave erosion along parts of the shoreline of a lake. Sediment is moved by wave action to other parts of the lake. Coarse sediment form beaches along parts of the shoreline. The predominant movement of lake sediments by wave action is usually in the direction of the longest fetch. Temporary changes to flow and water levels can be caused by: dewatering and flushing during construction activities.

Backwater Effects The backwater effects of structures on upstream flood lines are to be accounted for in the hydraulic calculations. Flood levels and flood line maps should be adjusted as structures are added or replaced. Low Flows Adequate downstream flow shall be maintained during construction to protect the interests of riparian owners and to ensure the continued sustainability of aquatic resources dependent on the stream.

5.2.3 Erosion and Sedimentation The owner shall be advised that they will be responsible for any increased erosion and sediment damage which may occur on upstream (or downstream) property as a result of construction of works. Turbidity and sediment must be minimized downstream during construction of the works.

5.2.4 Natural Amenities Natural amenities are areas of streams, rivers, and lakes that can be used and enjoyed by the public and riparian owners and include beaches, vegetation, trees, unique physical features, scenic areas, areas for swimming, areas for canoeing and boating, and areas for fishing. The natural amenities may be a feature of the water, the bed, or the shores and the banks.



Natural amenities can be altered by flooding, erosion, sedimentation, channelization, diversion, or other means. Natural amenities on shores of lakes and rivers should not be destroyed or altered without a full evaluation of the trade-offs involved.

Lands Adjoining Lakes and Rivers Natural amenities on shores of lakes and banks of rivers that exist under natural conditions should not be destroyed by flooding or channelization works. and Natural amenities include beaches, trees, vegetation, scenic areas, and unique physical features. Water in Lakes and Rivers Natural amenities of existing waters in lakes and rivers including its quality should be preserved. 5.2.5 Navigable Waters Protection Act (NWPA)

Under the provisions of the NWPA, it is unlawful to construct or place a dam, boom, causeway or bridge, or a work which interferes with navigation. MNR shall not grant location approval until Transport Canada has provided NWPA approval.

5.2.6 CA Generic Regulations Many CA’s have made regulations under The Conservation Authorities Act (Development, Interference with Wetlands and Alteration to Shorelines and Watercourses Regulation) which require that a permit be obtained authorizing the placement of fill in a regulated area, the construction of a structure (including a dam) in a flood plain, or the altering of a watercourse. 1) When an Application for Approval for works (other then a water crossing or

channelization) which are to be located within a CA is received, the CA shall be advised of the proposal and given the opportunity to comment, within 30 days, on the application to determine if the proposal would conflict with the policies, criteria, or programs of the Authority before granting an approval under the LRIA.

2) If the CA comments within 30 days that the proposal conflicts with CA policies,

criteria, or programs but does not conflict with Ministry policies, etc., and would otherwise be granted approval under the LRIA, the Application for Approval should be held in abeyance pending resolution.

5.2.7 Aquatic Ecosystem For LRIA applications involving water crossings and channelization works, MNR will meet its requirements related to the use, management and perpetuation of fish under the LRIA through the review under the Fisheries Act by DFO/CA staff. Referral of LRIA Applications to DFO In order to meet the purposes of the LRIA related to the perpetuation of fish, MNR will rely on and refer all LRIA applications for works in or around water where fish habitat is



likely to be altered to DFO for review and authorization under the federal Fisheries Act. DFO will provide advice and consider all habitat provisions of the Fisheries Act in their review of LRIA applications. To further improve client services in Ontario, DFO has signed agreements with many Conservation Authorities to undertake review of project proposals under Section 35 of the Fisheries Act. A similar agreement also exists with Parks Canada for National Parks, National Marine Conservation Areas, National Historic Canals, and National Historic Sites. The referral process is described in greater detail in the publication “A Protocol Detailing the Fish Habitat Referral Process in Ontario”, dated August 2000, which outlines roles and responsibilities of DFO, Parks Canada, MNR, and Conservation Ontario. It is recommended that DFO/CA and MNR staff work together to ensure that any fish habitat concerns that may affect fisheries management objectives are identified during review under the Fisheries Act. Construction Timing Windows for Work In-Water MNR is the lead agency for setting timing windows for work in water. Timing windows are applied to protect fish migration, fish spawning, egg incubation periods and other sensitive stages within or adjacent to a proposed work in water. Timing windows vary geographically across the province and depend on the species of fish present. MNR will set timing windows for work in water which protect fish spawning and egg incubation periods and other sensitive stages. Application of timing windows is consistent with MNR’s responsibility to manage fish populations. There may be other site-specific reasons (e.g. bird nesting, wildlife habitat) that timing windows may be applied.

5.2.8 Wildlife and Wildlife Habitat Applications submitted under LRIA will consider the impact of proposed work on wildlife and wildlife habitat. Lakes, rivers and wetland areas (including marshes, bogs, swamps and fens) often provide ecological habitat features that are important to wildlife. Significant wildlife habitat should be protected. Wildlife habitat can be divided into four broad categories:

1. Seasonal concentration areas; 2. Rare vegetation communities or specialize habitat for wildlife; 3. Habitats of species of conservation concern; and 4. Animal movement corridors.

Valuable riparian wildlife habitat should also be protected, and when appropriate, wildlife species considerations should be made for:

1. Semi-aquatic furbearers (e.g., beaver, otter, mink, muskrat, etc.); 2. Waterfowl (e.g., ducks, geese); 3. Waterbirds (e.g., great blue heron, black-crowned night-herons, great egrets,

etc.); and 4. Other wildlife species that frequent wetlands (e.g., moose).



Existing wildlife movement corridors (both along and across the waterbody) should be maintained to ensure that sufficient wildlife passage can still occur. A water crossing, or channelization should not be located on a lake or river on which a marsh, swamp, or bog exists in which significant wildlife habitat will be flooded, drained, or otherwise destroyed by construction and/or operation of the works unless impacts can be mitigated to the satisfaction of MNR. Significant unnatural fluctuations in water levels may negatively impact wetland obligate bird species, particularly species that nest on floating vegetation mats (e.g., loons, grebes, etc.). 5.2.9 Species at Risk Generally speaking, LRIA approval will not be granted for works that damage or destroy the habitat of, or kill or harm, an Endangered or Threatened species on the Species at Risk in Ontario list as designated by the Endangered Species Act, 2007 (ESA) The proposed location for a works and any area to be flooded should be checked to determine if habitat for Endangered or Threatened species may be damaged or destroyed by the construction or flooding and, if so, brought to the attention of the appropriate authority for assessment.

The Endangered Species Act, 2007 makes it an offense to kill or harm, or to damage or destroy the habitat of, an Endangered or Threatened species unless authorized under the ESA. The Federal Species at Risk Act (SARA) contains a List of Wildlife Species at Risk. The habitat of these species must also be included in the above assessment. 5.2.10 Wetlands Applications submitted under the LRIA will consider the impact of proposed work on provincially significant wetlands (PSW). Wetlands on lakes, rivers and in riparian areas provide important ecological, hydrological and socio-economic values. PSW’s should be protected. Please refer to the “Wildlife and Wildlife Habitat” and “Species-at-Risk” sections for additional information on these values. A water crossing, dam or channelization should not be located on a lake or river on which a PSW will be flooded, drained, or otherwise destroyed by construction and/or operation of the works unless it has been demonstrated that there are no negative impacts on the natural features or ecological functions which make the wetland provincially significant. In particular, work is to be timed and carried out such that there are no negative impacts on wetland hydroperiod.

The PPS, 2005 defines negative impacts in two three ways, some or all of which will be relevant which can be applied to wetlands:

1. In regard to the water policies, degradation to the quality and quantity of water, sensitive surface water features and sensitive ground water features, and their related hydrologic functions, due to single, multiple or successive development or site alteration activities;

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2. In regard to fish habitat, the harmful alteration, disruption or destruction of fish habitat, except where, in conjunction with the appropriate authorities, it has been



authorized under the Fisheries Act, using the guiding principle of no net loss of productive capacity; and

3. In regard to other natural heritage features and areas, degradation that threatens the health and integrity of the natural features or ecological functions for which an area i identified due to single, multiple or successive development or site alteration activities.

5.2.11 Expiry of Location Approval The Location Approval will contain a deadline that identifies the timeframe within which an applicant must submit Plans and Specifications. If the deadline for submission of Plans and Specifications is not met, then the Location Approval expires. 5.2.12 Water Crossings and Channelizations Table 2-4: Location Approval Information Required For Channelization Works For Water Crossings Channelization works to straighten, widen or deepen a channel, diversions, dredging, revetment walls, off-line ponds channel enclosures and covers > 20 m., installation of pipelines, cables, heat loops, water intakes and service cables Aquatic ecosystems approval as

determined by DFO (upon referral of application to DFO by MNR)

Approval of timing window by MNR

Approval from CA under the Conservation Authority Act

Approval from Transport Canada under the Navigable Waters Protection Act

Approval from the Ontario Ministry of Transportation for works located near provincial highways, public bridges and culverts

Applications must demonstrate that impacts to fish and wildlife, wetlands and species at risk have been considered.

Water crossings include bridges, culverts, channel enclosures less than 20 m and causeways. Structures with a bearing support

span of more than three (3) meters should be designed in accordance with Canadian Highway Bridge Design Code CAN/CSA S06-06.

The required information can vary from a few simple plans for a small culvert installation to a set of complex plans and specifications for a large bridge or culvert with high roadway fill embankments and approach roads.

Aquatic ecosystems approval as determined by DFO (upon referral of application to DFO by MNR)

Approval of timing window by MNR

Approval from CA under the Conservation Authority Act

Approval from Transport Canada under the Navigable Waters Protection Act

Approval from the Ontario Ministry 2010 33The changes in provincial policies, standards and practices contained within these draft technical guidelines are being presented for discussion purposes only and do not represent any commitment by government to change existing requirements for the construction and management of dams.



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of Transportation for works located near provincial highways, public bridges and culverts

Applications must demonstrate

that impacts to fish and wildlife, wetlands and species at risk have been considered.

1. Watershed Description 2. Location and Description of Existing

Channel Conditions 3. Description of Proposed Works 4. Inflow Design Flood (IDF) 5. Hydrologic and Hydraulic Analyses 6. Fluvial Geomorphological Assessment 7. Ecological Assessment (if required) 8. Geotechnical Field Investigations and

Analyses (if required)Structural and/or Slope Stability analyses (if Required)

1. Watershed Description 2. Location and Description of

Existing Channel Conditions 3. Description of Proposed Works 4. Inflow Design Flood (IDF) 5. Hydrologic and Hydraulic Analyses 6. Fluvial Geomorphological

Assessment 7. Geotechnical Field Investigations

and Analyses (if required) 8. Structural and/or Slope Stability

analyses (if Required) Final Design 1. Sealed final design drawings and

specifications “for construction”

Final Design

1. Sealed final design drawings and specifications “for construction”

Electronic and hard copy of all hydro-technical computer simulations including input and output.

Electronic and hard copy of all hydro-technical computer simulations including input and output.

Additional Information Check for applicability of: -EAA -CEAA -NWPA -OWRA


CHAPTER 6.0: PLANS AND SPECIFICATIONS APPROVAL 6.1 Water Crossings and Channelization Works Works that are submitted for Plans and Specifications Approval under LRIA are required to provide specific information in the form of a Design Report including:

1. Hydrological Information; 2. Hydraulic Information; 3. Foundation Information; 4. Design & Construction Information; and 5. Ecological Information.

The information requirements and considerations associated with water crossings, channelization works and sedimentation & erosion controls are discussed more fully in Chapters 2,3, and 4. Once the above information has been submitted and has been reviewed and determined to meet all the requirements, a Plans and Specifications Letter of Approval is issued and the applicant can begin construction. Should the application be considered as incomplete, the applicant will be notified to provide the additional information or clarification and resubmit it for review. Table 2-5: Summary Checklist of Information Requirements for Volume 2 Plans and Specifications Approval

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Types of Information Requirements Types of Work 1 Application form information All 2 Location approval information All Hydrologic and Hydraulic Analyses 3 Inflow design flood All 4 Stage-storage-discharge calculations All 5 Floodplain mapping All 6 Hydraulic capacity calculations All 7 Channel velocity calculations All 8 Travel time calculations (time to peak and time of

concentration) channelizations

9 Channel and bank protection All 10 Fluvial Geomorphological Assessment All Geotechnical field and office Investigations and

Calculations

11 Structure All 12 Channel diversion channelizations 13 Stability calculations Retaining walls Soils Analysis 14 Classification (United Soils Classification System) All 15 Soil strength All



16 Bearing capacities All except channelizations

17 Erosion and Sediment Control Plan All Additional Information 18 Construction Drawings and Specifications All 19 Construction Timing Windows All 20 Report(s) documenting that criteria and standards have

been met All

21 Location approval expiration date and work permit form All Environmental Analyses 22 Habitat assessment All

Table 2-5 above documents a checklist of standard requirements. It should be noted however, that the extent of the documentation required will largely be determined by the Project Engineer affiliated with MNR’s Regional Engineering Services Unit (RESU). This determination will be made on a case-by-case basis and in response to the proposal under review.

Note to Applicants: While the above summarizes the documentation required for applications to be considered for approval, Applicants and/or their Agents are directed to contact the District Area Supervisor of the local MNR District Office with any questions concerning the Ministry’s documentation requirements. 6.2 Design Report Channelization Works: The amount and type of information required will depend on the extent to which the main channel and flood plain of the natural stream is to be altered or otherwise affected. Water Crossings: The amount and type of information required will depend on the extent to which the flood plain and low flow channel is to be altered or otherwise affected. 6.2.1 Hydrological Information Table 2-6: Hydrological Information Required Channelization Works Water Crossing



The hydrologic information must include hydrologic analyses for the 2-year flood up to and including the Hazard Flood Limit or Regulatory Flood (RF).

The design flood magnitude must be established in accordance with Table 2.3.1 and Table 2.3.2 and have regard for other relevant Ministry of Transportation Road Crossing standards. The following information is required: 1) Inflow Design Flood and magnitude; 2) Regulatory Flood and magnitude; and 3) Inflow design flood hydrograph including

channel and reservoir flood routing, where applicable

6.2.2 Hydraulic Information Table 2-7: Hydraulic Information Required Channelization Works Water Crossing Hydraulic information will be required for works that will increase flow capacity and/or decrease flood plain storage. This could result in increased flooding in downstream reaches unless storage compensation is provided. The following information is required: 1) Design parameters and assumptions; 2) Maximum and minimum discharge

capabilities; 3) Flows and velocities in the channel

and flood plain for water levels corresponding to the return period flood events;

4) Stage-detention storage curve(s) in 0.3 metre elevation increments from the channel bed to the Regulatory Flood level;

5) Stage-discharge curve(s) in 0.3 metre elevation increments from the channel bed to the Regulatory Flood level;

6) Energy dissipation details downstream of water crossings (where required); and

7) Channel and bank protection details. All work, including the upstream and

Hydraulic information will be required for the works to ensure that no increase in upstream water levels are created affecting riparian rights. Hydraulic analyses and calculations must include: 1) Design parameters and assumptions; 2) Existing water level and high water

mark (see glossary); 3) Design flood level for the watercourse

and flood plain; 4) Calculations/simulations to determine the

flood plain backwater elevations and channel velocities under existing conditions and proposed conditions;

5) Stage-discharge-velocity table(s) under existing and proposed conditions for the river at the bridge site; and

6) Channel and shore protection details. All work, including the upstream and downstream channel transitions, shall be designed to handle ice and debris, protect the work, and resist anticipated high-water velocities.



2010 38

Channelization Works Water Crossing downstream channel and infrastructure, must be designed to handle ice and debris, protect the work, and resist anticipated high water velocities. 6.2.3 Fluvial Geomorphology Information Table 2-8: Fluvial Geomorphology Information Required Channelization Works Water Crossing Fluvial geomorphological information will be required for works that will alter geomorphic characteristics of the channel and its riparian floodplain, potentially altering sediment transport, bank and bed stability. The following information is required (at a minimum): 1) Confirmation of project requirements; 2) Dimension, Pattern and Profile data; 3) Sediment and (sub)pavement data; 4) Historical and future trends

assessment; 5) Characterization of study area; 6) Channel and bank protection details;

and 7) Completion of 9 step process as per

Adaptive Management of Stream Corridors in Ontario, MNR, 2001.

All work, including the upstream and downstream channel and infrastructure, must be designed to handle sediment, flow, ice and large woody debris. The channel should function properly at low flow, bankfull flow and flood flow levels.

Fluvial geomorphological information will be required for works that will alter geomorphic characteristics of the channel and its riparian floodplain, potentially altering sediment transport, bank and bed stability. The following information is required: 1) Confirmation of project requirements; 2) Hydrology and bankfull flows; 3) Dimension, Pattern and Profile data; 4) Sediment and (sub)pavement data; 5) Characterization of study area; and 6) Channel and bank protection details. All work, including the upstream and downstream channel and infrastructure, must be designed to handle sediment, flow, ice and large woody debris. The channel should function properly at low flow, bankfull flow and flood flow levels. The proponent should reference the DFO “Stream Simulation Design” process.

6.2.4 Foundation Information Table 2-9: Foundation Information Required Channelization Works Water Crossing Both the design and foundation conditions will determine the need for and extent of information gathered. The design methods

Both the design and foundation conditions will determine the need for and extent of information gathered. The design methods



and calculations will vary depending on the proposed design. A soil investigation will be required at sites where information is unknown. The degree of investigation will be site-specific and may involve geotechnical engineers. For most work, consideration must be given to bearing capacity, passive and active soil pressure, materials (filters) compactability, and erosion protection set on natural conditions.

and calculations will vary depending on the proposed design. A soil investigation will be required at sites where information is unknown. The degree of investigation will be site-specific and may involve geotechnical engineers. For most work, consideration must be given to bearing capacity, passive and active soil pressure, materials (filters) compactability, and erosion protection set on natural conditions.



6.2.5 Design and Construction Information Table 2-10: Design and Construction Information Required Channelization Works Water Crossings

In providing documentation to describe the works to be completed, Applicants should describe or demonstrate the following:

1. For private lands legal right to construct the project and flood the land, obtained by ownership or otherwise;

2. For Crown lands License of Occupation, Easement, or Lease under the Public Lands Act for a worksite;

3. Hydrological (watershed) calculations;

4. Hydraulic calculations (i.e. water crossings);

5. Geotechnical investigations and/or considerations for structures;

6. Detailed plans and specifications for location, design, construction, including construction drawings and specifications sealed by a Professional Engineer as required;

7. Details concerning the proposed method of construction, proposed scheduling of construction, site access, phasing and timing. In this regard, a specified time period for the completion of construction of the work (in whole or in part), including all in-water work including temporary control works, must be included for review and approval or added as a condition of approval;

8. Erosion and sediment control plan; 9. Area to be permanently flooded by

the proposed work; and 10. Map of the watershed

The channel and infrastructure design and/or assessment must be provided as design calculations and drawings. Design calculations should include:

1. All assumptions and input parameters/criteria;

2. Stability calculations for

overturning, sliding, and overstressing; and

3. Infrastructure testing, analysis, and

recommendation

4. Design drawings should include: a) General arrangement drawings

in plan view of the work showing any legal constraints;

b) Location and elevation of

buildings, septic tank tile fields, wells, historical or archeological sites, in or adjacent to the (proposed) flooded area;

5. General arrangement drawings in

plan view of temporary facilities, e.g., cofferdam, staging and disposal areas; a) Sufficient plans, profiles, cross

sections, and details showing:

b) Existing conditions, e.g., channel alignment;

i. Surface and subsurface conditions;

ii. Proposed work, e.g., channel alignment, length, side and bottom slopes, channel lining, or other surface protection;

iii. All natural and proposed water levels, to geodetic

For New Works For new works, applications must be accompanied by:

1. A copy of the Location Approval condition and requirements, supporting documentation and any other agency from whom approval



datum; iv. All infrastructure related

to the work, e.g., drop structures or energy dissipaters and transition sections.

c) A sediment and erosion control

plan Specifications for materials and equipment related to infrastructure must also be submitted as part of the final design. Area to be permanently flooded by the proposed work; and Map of the watershed.

has already been obtained; 2. Copy any site inspection report

documenting the MNR District Area Team’s findings and recommendations.

6.2.6 Ecological Information (Aquatic and Terrestrial) Table 2-11: Ecological Information Required Channelization Works Water Crossings For work where there are potential concerns around impacts on aquatic or terrestrial resources, a section of the design report shall include assessment and mitigation impacts on the following items: 1) Channel changes; 2) Natural conditions, scour, and

sediment load; 3) Lake changes, e.g., littoral drift; and 4) Fisheries. 5) Wildlife. 6) Wetlands. 7) Species at risk

For work where there are potential concerns around impacts on aquatic or terrestrial resources, a section of the design report shall include assessment and mitigation impacts on the following items: 1) Channel changes; 2) Natural conditions, scour and sediment load; and 3) Fisheries; 4) Wildlife; 5) Wetland 6) Species at risk.




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Volume Two: References D’Eon, R.G., The Beaver Handbook: A Guide to Understanding and Coping with Beaver Activity, NEST Field Guide FG-006, March 1995 Holling, C.S., Adaptive Environmental Assessment and Management, New York: John Wiley & Sons, 1978 Government of Ontario, Ministry of Natural Resources, Adaptive Management of Stream Corridors in Ontario (2001) Government of Ontario, Department of the Environment, Storm Water Management Planning and Design Manual, 2003 Government of Ontario, Ministry of Natural Resources Technical Guide River and Streams Hazard Flood Limit (2001) Government of Ontario, Ministry of Transportation Design Flow Standards, January 2008 Government of Ontario, Ministry of Transportation Crown Land Bridge Guidelines, February 2008 Trow Consulting Engineers Ltd., Instream Sediment Control Techniques Field Implementation Manual, NEST Field Guide FG-007, January 1996 Wilson, R.G, “CSP Culvert Installation at Water Crossings on Forest Access Roads”, Technical Note TN-013, May 1996

technical guidelines and requirements for approval …3.3.6 total diversion/relocation of the river...

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