FOREWORD - Renaud

1 FOREWORD The Ministry of Transportation of Ontario firmly believes in good drainage management practice in highway development projects. Good drainage management protects highway infrastructures, property owners and users against flood and drainage-related safety hazards. At the same time, good drainage management protects the land and water environments in watersheds impacted by highway projects and assists in conservation. The ministry believes that good drainage management practice starts with practitioners and decision makers embracing an attitude of respect for the natural environment and willingness to work cooperatively with it in development of highway projects. Practitioners with an understanding of up-to-date concepts and principles of good drainage management practice as well as necessary professional skills to accomplish their work can achieve transportation objectives as well as providing for the natural environment.

2 To these ends, the ministry has developed the MTO Drainage Management Manual to facilitate and direct drainage management practice within the ministry. It will be used by ministry staff of all levels as well as consultants working on provincial highway project assignments. This manual should be used in conjunction with ministry directives which set objectives of practice and general design criteria. Also, this manual is intended to be used within the highway planning and design process and the class environmental assessment process. Two existing publications, namely, MTC Drainage Manual of various dates from 1980 to 1988, and MTO Drainage Management Technical Guidelines dated November, 1989 are now replaced by this manual. Applicable materials in these two publications have been incorporated into the manual. This manual does not set standards for parties and projects external to the ministry.

3 However, the ministry hopes that it will be useful to land developers, municipalities, conservation authorities and their respective consultants in understanding the ministry's drainage management practice. It should also help external parties to understand concerns the ministry may have with regard to drainage management proposals affecting the provincial highway corridor. This manual is the result of the efforts of many, including the MTO Drainage Management Manual Advisory Committee; the Editorial Panel and the writing teams. Participants included both ministry staff and external individuals and organizations. Input from regional offices has notably influenced the outlook and contents of the manual resulting in a document that reflects current operational issues and needs of users. The ministry wishes to thank all who were involved (names appear in the Acknowledgements inside the manual) October 1997 DISCLAIMER The MTO Drainage Management Manual (the manual) has been developed for use by the Ministry of Transportation of Ontario for its provincial highway projects.

4 Other prospective users should determine for themselves whether the manual is applicable to their practices before they use the manual. The responsibility for the decision is the practitioners'. The ministry expressly disclaims responsibility for any inaccuracy or error which the manual may contain or for the fitness of the manual or the validity of the information contained in the manual for any particular purpose, or for any damage or loss which any person may suffer as a result of reliance upon any statement which the manual may contain. iii Preface The Scope of This Manual This manual has been developed for use by the staff and consultants of the Ministry of Transportation of Ontario (MTO). It covers the practice of drainage management normally associated with the planning and design of highway projects. This manual deals with drainage practice issues such as: developing solutions to flood plain concerns associated with the selection of highway horizontal and vertical alignments; incorporating watershed drainage concerns when determining tradeoffs between highway alignments, property acquisition, and modifications of streams to accommodate highways; and using engineering knowledge of stream morphology to select suitable locations for bridges and culverts.

5 The manual provides methodology for the hydraulic design of a variety of drainage facilities. These include: roadside ditches, sewers, pavement and bridge deck drainage, stormwater ponds, bridges, culverts, stream channel works, and temporary erosion and sediment control works on construction sites. Generally, applicable standards of practice are included in the discussion of the practice and design methodology. This includes guidance on issues such as acceptable design standards for hydraulic analysis of bridges and culverts. However, to maintain the flexibility of the document specific design policies and criteria are not included in the manual, since policies and criteria change more often than design methodology. Policies and criteria may also vary with geographical settings, and for a given project special conditions may require flexibility in setting the design criteria.

6 Moreover, this manual may be used by parties external to MTO to whom MTO directives may not apply. MTO users should not be unduly inconvenienced by the absence of specific MTO design policies, referred to as "directives" in the manual, since all MTO offices maintain a complete, up-to-date set of policies which is readily accessible to all staff. It should be noted that specific design objectives, criteria, and options for an individual highway project, including the drainage management components, will be established by the project through the class environmental assessment process. The material presented in this manual provides the general ground work for developing project specific requirements. It is intended to be read and used in this context. Design tools such as computer models, and reference materials mentioned, but not included in the manual, are not part of this document.

7 Such material should be acquired directly from the appropriate suppliers. Transportation engineering is a multidisciplinary field of engineering of which drainage management practice is but one component. Therefore, users of this manual should use this document in conjunction with other applicable manuals and in consultation with the practitioners from the other disciplines. These disciplines include: highway geometric design, structural engineering, environmental planning, and landscaping, to name a few. MTO Drainage Management Manual iv Finally, it is important to recognize that the Drainage Management Manual is formed around the three basic tasks ( develop study options, preliminary design, and detail design) that are fundamental to the planning and design of highways and their drainage systems. The advantages of this task-oriented organization are as follows.

8 Over time, the mode used to undertake and deliver the planning and design of highway projects may change. For instance, the planning and design of highways may be out-sourced to the private sector. Since the tasks associated with the planning and design of highway drainage systems do not change, all practitioners can use the manual, regardless of whether they are MTO staff or agents who act on behalf of MTO. Over time, the process that drives the planning and design of highways may change. Since the manual is not tailored to suit a specific step-by-step process, it can adapt to any process-oriented changes because the fundamental tasks will not change. Drainage Management Practised in This Manual Drainage management practised by this manual may be described by its basic concept, objectives, and scope of application. The basic concept of drainage management in MTO is adapted from that suggested by the Ministries of the Environment and Energy (MOEE) and Natural Resources (MNR) in the two publications: Integrating Water Management Objectives into Municipal Planning Documents and Subwatershed Planning, 1993.

9 The main point of this concept are as follows. Watersheds and subwatersheds are the basic Planning units for land use planning and resources management. The community of living things should be considered along with the physical and chemical factors which form the environment. The main premise is that a wholesome natural environment is achieved over the long term when the environmental considerations are balanced with social and economical relationships. The watershed planning unit includes all water processes and factors involved in the hydrological cycle. The subwatershed planning process emphasizes the following considerations: protection is preferred to mitigation; understanding of the interactions of the components of the natural environment is encouraged; and watershed planning is expected to be a multidisciplinary and consultative process.

10 The drainage management objectives of MTO include those required for the protection of the natural environment, as mentioned in the MOEE/MNR publications, and those required to fulfil the provincial transportation business mandate. The transportation objectives include: provide transportation infrastructures for the movement of goods and people; provide efficient and safe operating conditions of highways in wet weather; protect transportation infrastructure investments against damage by floods, scour, and other long-term hydrologic factors; protect watershed lands upstream and downstream of highway right-of-ways from drainage impacts attributable to highways; and achieve best return on investment for drainage management in transportation infrastructures. In applying the watershed planning concept mentioned previously, drainage management in Preface vtransportation engineering will focus its scope on watershed areas involving highways directly or indirectly.