2. PURPOSES AND OBJECTIVES OF CIVIL ENGINEERING PLANNING AND MANAGEMENT

Transcription

1 2. PURPOSES AND OBJECTIVES OF CIVIL ENGINEERING PLANNING AND MANAGEMENT Civil engineering planning and management is used to: (i) determine what measures (structural and nonstructural) should be employed to meet the needs of population; (ii) take advantage of opportunities for infrastructure development; and (iii) preserve and enhance land, water and related natural resources. The following section focuses on water resources sector as an example of broader scope of civil engineering activities. Similar discussion and scope could be developed for transportation, structural, geotechnical or other civil engineering sectors. 2.1 Purposes of Water Resources Planning and Management Water resources are controlled and regulated to serve a wide variety of users. Flood control, drainage, sewerage, are some of the examples of water engineering activities used for the control of water and minimization of destructive impacts. Municipal, industrial, and irrigation water supply, hydropower generation, and navigation are some of the examples of the utilization of water resources for beneficial purposes. Also, water resources are being managed for the purpose of water and environmental quality control. In the most general way the purposes of water resources planning and management can be listed as follows: Water supply for municipal & industrial uses; Water supply for rural uses; Water supply for thermal-electric power plants cooling; Water supply for irrigation; Flood control and damage prevention; Hydroelectric power generation; Navigation; Water quality management; 1

2 Wastewater treatment and disposal; Flow augmentation; Recreation; Commercial fishing and trapping; Drainage; Sedimentation control; Land stabilization; and Erosion control. In addition to the purposes and functions, for which economic benefits can usually be estimated, the environmental awareness has encouraged development of water resources for preservation and enhancement of: Natural water and related land areas (including aesthetic values); Archeological, historical, biological and geological resources; Ecological systems; and Water, land and air quality. Planning, development, and management of water resources may also be used to include: Regional economic development; Income distribution; Health and safety; Educational and cultural opportunities; Emergency preparedness; and Other measures to improve the quality of life. Typical water resources projects are very complex and involve different specialties. An outline of tasks for planning an urban flood control project may be used for illustration of the complexity: 1. Project management and coordination; 2. Analysis of basic data (maps, aerial photos, streamflow record, etc.); 3. Determination of needs for flood control: 2

3 - Flood zoonning - Floodplain characteristics - Future activities in flood area - Estimates of existing and future flood damages; 4. Consideration of alternative ways of meeting needs: - Upstream reservoir - Local protective works - Nonstructural measures; 5. Reservoir studies; - Site selection - Capacity selection - Selection of dam and spillway type - Layout of structure - Analysis of foundations of structures - Construction plan - Cost estimates of structures - Access roads, bridges, camp etc. - Requirements for land, reallocations, etc. - Consideration of reservoir for multipurpose use; 6. Studies for local protective works: - Levees, floodwalls, river shaping, interior pumping stations; 7. Studies of nonstructural measures: - Land use controls - Flood warning systems - Flood proofing, etc.; 8. Formulation of optimal combination of structural and nonstructural components for flood control project; 9. Economic analyses; 10. Financial analyses; 3

4 11. Assessments of environmental impacts: - Ecological - Archeological - Historical - Geological, etc.; 12. Sociological impact assessment; 13. Public information and participation programs; and 14. Report preparation. The list of tasks for flood control project indicates that at least the following skills would have to be represented: 1. Engineers - Civil - Structural - Hydraulic - Hydrologic - Geotechnical - Construction - Mechanical - Electrical - Surveying, etc.; 2. Urban/regional land planning specialists; 3. Architects; 4. Economic and financial specialist; 5. Environmental specialists; - Biologists - Forest engineers - Zoologist, etc.; 6. Sociologists; 7. Real estate and relocation specialists; 4

5 8. Public information specialists; and 9. Report production specialists. Complexity of purposes for which the water resources are developed makes each project a challenging task for teams of specialists. Successful completion of the project requires careful identification and understanding of all the purposes. Some of them can be conflicting, and some can be hard to quantify. However, the fact is that in the future we will be dealing exclusively with multipurpose projects. Number of appropriate available sites is diminishing with great speed, and demand for water is increasing in almost all sectors. 2.2 Civil Engineering Analysis Objectives Civil engineering planning and management process is a search for the solution of how to meet the needs of population (for shelter, transport, water, energy, etc.) with the available resources (Burges, 1979; Major and Lenton, 1979; Goodman, 1984; Environment Canada, 1987; United Nations, 1988). Civil engineering planning and management is as old as humanity. However, with knowledge and technology development, change in living standard of people and further economic development, the analyses procedure changes Principle Objectives for Industrialized Countries An example of principle water resources planning and management objectives for industrialized countries is based on the "Principles and Standards for Planning Water and Related Land Resources" used in USA and introduced by the US Water Resources Council in 1973 and modified in 1979 and 1980 (US WRC, 1973). According to them the overall purpose of water resources planning and management is improvement of the quality of life through contributions to :(a) national economic development; (b) environmental quality; (c) regional economic development; and (d) other social effects. Under the "Principles and Standards" the water resources planning process consists of six major steps: (i) specification of the water and related land resources problems and opportunities; (ii) inventory, forecast and analysis of water and related land resource conditions within the planning area relevant to the identified problems and 5

6 opportunities; (iii) formulation of alternative plans; (iv) evaluation of the effects of the alternative plans; (v) comparison of alternative plans; and (vi) selection of a recommended plan based upon the comparison of alternative plans. Canadian government in 1987 has realized that we must start viewing water both as a key to environmental health and as a commodity that has real value, and begin to manage it accordingly (Environment Canada, 1987). Two main goals have been identified with respect to water: (1) to protect and enhance the quality of the water resource; and (2) to promote the wise and efficient management and use of water. Five strategies have been proposed to reach stated goals as broad courses of action which define a supportive flexible role for the federal government that enables the various federal agencies, other levels of government, and industry to respond to their particular circumstances and challenges. These broad courses of action are adopting over time to changing circumstances and new water-related concerns. They include: (i) water pricing; (ii) science leadership; (iii) integrated planning; (iv) legislation; and (v) public awareness Principle Objectives for Developing Countries Civil engineering planning and management in developing countries should correspond to a set of criteria distinct from those used in industrialized countries. These criteria should reflect prevailing constraints on physical, financial and human resources and the need to allocate critically sparse resources to programs that correspond to short and long-term socio-political objectives and promise to be the most cost effective. The United Nations Industrial Development Organization (Dasgupta et al, 1972) recommended that planning analysis considers the following objectives: (i) aggregate consumption; (ii) income redistribution; (iii) growth rate of national income; (iv) employment level; (v) self-reliance; (vi) merit wants. UN publication treats the problems of evaluating the extent to which projects advance each of the objectives and present their combination as a measure of "aggregate economic profitability". The UNIDO guidelines, in developing a system of objectives, do not lay any stress on the quality of the environment or other intangible descriptors applied to the quality of human life. 6

7 In response to contemporary requirements of civil engineering planning the United Nations Department of Technical Co-operation for Development has produced modified guidelines for developing countries (United Nations, 1988). They are aimed at producing action documents keyed to the goals, needs and desires of the region and the country for which planning is conducted. They are addressing the main elements of civil engineering project planning specific to developing countries as: (a) spreading investments over time according to budgetary constraints, while attempting to maximize benefits; (b) assuring the divisibility of schemes into elements which can be implemented gradually; (c) phasing large projects, avoiding over-design of systems and minimizing idle sunk costs; and (d) promoting sustainability of the project through involvement of the community. These guidelines implemented to the efficient use of water, for example, emphasize: (i) reduction in water losses (domestic water supply, irrigation, and industrial water use); (ii) improvements in water quality (sources of water pollution, and water quality management); (iii) conjunctive use and artificial recharge; and (iv) the use of non-conventional sources of water (brackish and sea water, reuse of waste water, and weather modification). 2.3 Alternative Objective Structures in Civil Engineering Planning and Management Civil engineering systems are characterized by high level of complexity. Therefore, the objectives used in the analysis of civil engineering systems have complex structure too. Decomposition process is adopted in practice to deal with the complex structure of objectives. One way of decomposing the objective structure is illustrated in Figure 2.1. Focusing again on water resources sector, the following meaning can be assigned to the objectives in Figure 2.1: G 0 - maximum of integral water use, water protection, and protection from water; G 1 1 G minimum municipal water supply shortage (m 3 /sec); - minimum irrigation water supply shortage (m 3 /sec); 7

8 1 G 3 1 G n 2 G 1 2 G 2 2 G 3 2 G m - maximum water quality (BOD, DO, TDS); - minimum flood damages ($): - minimum cost of water supply network ($); - minimum error in the population prediction (%); - minimum reservoir capacity (mil m 3 ); - maximum irrigation canal capacity (m 3 /sec); and so on. G 0 r 0 n r 0 1 G 1 1 G1 2 G1 3 G 1 n.... r 1 11 r 1 12 r 1 nm G 2 1 G 2 2 G 2 3 G 2 m Figure 2.1 Decomposition of objectives with and structure In this context the objectives are connected with so called and logic: 1 1 { q} 1 1 j 1 G G G... G G (2.1) p what means that the highest rank objective will be satisfied only if all the objectives of lower rank are satisfied. The interrelations between the objectives are defined by the set: 8

9 j { r ik } R = (2.2) To have the complete objective structure the introduction of time (t s ) is necessary. So finally the complete representation of objectives connected with and structure is mathematically defined by the triplet: G s { G R t } =,, (2.3) s In practice, the development of objective structure can start from the top going downward, as well as from the bottom going upward. The first approach is used for the system synthesis. The second approach is used in the case of partial, or phase planning of civil engineering systems known as the system analysis. Mathematical representation of modified equation (2.3) for the application in system analysis is: 1 {,, a } G = G R t s (2.4) where: t a denotes the time necessary to achieve a particular objective in the analysis. The second way of decomposing objectives (Figure 2.2) is used in the case of alternative objectives, or objectives connected with so called or logic. An illustrative example for the structure in Figure 2.2 can include the following objectives: j G i j-1 G 1 j-1 G 2 - maximum hydro-power generation; - maximum reservoir release; - minimum production cost; and so on. The civil engineering planning and management objectives can be expressed using different units for expressing system effectiveness. The most common are: Quantitative units (volume, m 3 ; concentration of DO, mg/l); 9

10 Probabilistic units (system reliability, % of failure; flood frequency, %); Economic units (monetary value, $); Time units (hour, hr; day; month); and Estimate on the un-dimensional scale (for example from 1 to 5 where 1 is bad and 5 is excellent). G i j G 1 j-1 G n j-1 Figure 2.2 Decomposition of objectives with or structure The civil engineering objectives can be expressed in few different forms. Some of them are: Inequality objectives. This form is used when the required effects (RE) must be smaller or greater then some threshold value (GE) (reliability of energy supply must exceed 95%; etc.). RE i GE (2.5) i Equality objectives. This is a very rigid objective form usually expressed as: RE i = GE (2.6) i Extremization objectives. 10

11 RE i extremum (2.7) When the objective structure is defined, the next step in the process is mathematical formalization of civil engineering planning and management criteria or objective functions. Their main application is in optimization analyses of civil engineering systems. Civil engineering planning and management criteria are defined by the sixplet: { C Q P T V I} J:,,,,, (2.8) where: C - represents economic measure of system performance expressed in monetary units (benefits; damages; costs; etc.); Q - quantitative measure of system performance defined by system outputs or/and system state (pressure; water quality; etc.); P - probabilistic measure of system performance (reliability; vulnerability; resiliency; robustness; etc.); T - time measure of system effectiveness; V - estimate of immeasurable system characteristics (system security; importance of phase construction; social impacts; etc.); I - estimate of system interactions with other systems and system environment (ecological impacts; international cooperation; etc.). Different objective functions can be formed using the general definition in equation (2.8). The current engineering practice is mostly using economic criteria, like: Minimization of total costs (capital and maintenance and operations); Maximization of net benefits (B-C); or Maximization of benefit cost ratio (B/C). Practice is still very rarely using objective function of the following type: ( physical effectsof CES) max imum (2.9) ( used resources) This type of objective function will be used more and more in the future with further increase in the use of recourses. The main effect of (2.9) is rational utilization of available resources. 11

12 2.4 Problems 2.1 Distinguish between multiple purposes and multiple objectives. 2.2 Present two examples of complementary and two examples of conflicting purposes of civil engineering projects. 2.3 Present two examples of complementary and two examples of conflicting objectives of civil engineering projects. 2.4 Discuss the use of benefits and costs as objectives for civil engineering systems analysis. 2.5 Give an example of the objective structure characterized by and logic. 2.6 Give an example of the objective structure characterized by or logic. 2.7 Describe the political, economic, technical, environmental, social, aesthetic, etc. issues involved in one civil engineering problem you are familiar with. 2.8 For the example in Problem 2.7 identify the objectives, both quantitative and qualitative. 2.9 For the quantitative objectives in Problem 2.8, indicate the indices of quantification that most appropriately reflect these objectives For the objectives in the Problem 2.8, indicate indices that might be reduced to common terms (e.g., dollars) References 1. Burges, S.J., Water Resources Planning in USA: , J. Water Resour. Plann. Manage. Div. Am. Soc. Civ. Eng., 105 (WR1), Canadian Water Resources Association, Sustainability Principles for Water Management in Canada, Cambridge, Ontario. 3. Dasgupta, P., A. Sen, and S. Marglin, Guidelines for Project Evaluation, United National Industrial Development Organization, Vienna. 12

13 4. Environment Canada, Federal Water Policy. 5. Goodman, A.S., Principles of Water Resources Planning, Prentice Hall, N.J. 6. Major, D.C., and R.L. Lenton, Water Resource Systems Planning, Prentice Hall, N.J. 7. United Nations, Water Resources Planning to Meet Long-Term Demand: Guidelines for Developing Countries, Natural Resources/Water Series, No.21., Dept. of Tec. Co-op. for Development. 8. US Water Resources Council, Principles and Standards for Planning Water and Related Land Resources, September 10, 1973; Rev. December 14, 1979; Rev. September 29, Wallis, J.R., Water Resources Approaching the Millennium, in Hydrology in Developing Regions...The Road Ahead, edt. by Lorentz, S.A., S.W. Kinzle, and M.C. Dent, Department of Agricultural Engineering, University of Natal, Republic of South Africa, vol I, pp