Introduction to Engineering Hydrology PDF

INTRODUCTION TO ENGINEERING HYDROLOGY PREPARED BY: ENGR. REYMORE ALFREDO INSAS TOPIC LEARNING OUTCOMES By the end of this lecture, the student should be able to: 1. Identify the different usage of water and some water challenges in their community; 2. Define what is hydrolo...

INTRODUCTION TO ENGINEERING HYDROLOGY PREPARED BY: ENGR. REYMORE ALFREDO INSAS TOPIC LEARNING OUTCOMES By the end of this lecture, the student should be able to: 1. Identify the different usage of water and some water challenges in their community; 2. Define what is hydrology and differentiate it from other water-related subjects most especially fluid mechanics and/or hydraulics; and 3. Illustrate and define the different processes in the hydrologic cycle.  ℎ WATER AS ESSENTIAL RESOURCE Water Supply (Domestic &  Industrial) Irrigation Transportation Hydropower Generation Recreational Purposes WATER CHALLENGES Increase in Population  Rapid Urbanization Climate Change WATER CHALLENGES WORLD FRESH WATER RESOURCE SUSTAINABLE WATER RESOURCES MANAGEMENT  Source: Mays (2011) WATER RESOURCES ENGINEERING  Water resources engineering is a vital subset of Civil and Environmental Engineering that focuses on planning, building, and designing systems to both build and maintain our water resources. While this includes a huge umbrella of topics, some of the largest aspects of water resources engineering stand out above others. WATER RESOURCES ENGINEERING ✓Flood Control and Drainage Design ✓Irrigation Engineering ✓Water Supply Planning and Development ✓Coastal Engineering ✓River Engineering ✓Ground Water Modelling WATER RESOURCES ENGINEERING The management and control of our water resources requires the conception, planning, and execution of designs to make use of the water or avoid damage from too much water. For most of the twentieth century this has been viewed as the work of civil engineers. It is becoming apparent that engineering structures are not always the preferred solution. In some cases, a non-structural solution is superior. This means that more alternatives must be considered in the planning phase and may require the service of other disciplines – economics, social and political science, biology, and geology. Each problem involves a unique set of physical conditions and constraints, which can be resolved by the careful coordination of the various disciplines. FIELDS OF WATER RESOURCES ENGINEERING Water is controlled and regulated to serve a wide variety of purposes. ✓Flood mitigation, ✓land drainage, ✓sewerage, and ✓highway culvert design are applications of water-resources engineering to the control of water so that it will not cause excessive damage to property, inconvenience to the public, or loss of life. FIELDS OF WATER RESOURCES ENGINEERING Hydraulic structures play an important role  in drainage, irrigation, and hydraulic projects. If hydraulic structures fail, it may cause serious damages of wealth, properties, and environment as well as losses of life and injury to economy. FIELDS OF WATER RESOURCES ENGINEERING Pollution threatens the utility of water for municipal and irrigation uses and seriously despoils the aesthetic value of rivers—hence pollution control or water-quality management has become an important phase of water resources engineering. Finally, the potential of nonstructural measures such as zoning for flood mitigation and the preservation of natural beauty are factors which the water-resources engineer  must consider. There has been a tendency toward specialization within these applications in the water-resources field, but actually the problems encountered and the solutions to these problems have much in common. FIELDS OF WATER RESOURCES ENGINEERING Courses in water resources engineering prepare students for positions in the public and private sector that require the following skills: ✓ Planning and designing water distribution systems, sanitary and storm water collection systems, and the pumping and storage infrastructure required by these systems ✓ Designing highway drainage systems and conveyance structures such as culverts and bridges. ✓ Managing floodplains and municipal streams and developing floodplain maps and management plans. ✓ Managing rivers and reservoirs for recreation, flood control, irrigation,  and other multi-use functions. ✓ Developing groundwater resources and remediating polluted groundwater resources. ✓ Designing the hydraulic features of new hydraulic structures such as dams, locks, hydroelectric stations, levees, erosion control measures, and many other applications. WATER RESOURCES ENGINEERING WATER RESOURCES ENGINEERING  In the Philippines, total renewable freshwater available is about 146 billion cubic meters (BCM) per year. Of this amount, about 86% is in the form of surface run-off (126 BCM/year) and the remainder is below the ground (20 BCM/year). Average rainfall is about 4,000 mm per year. The bulk of these water resources are distributed among the country’s 421 river basins, 18 of which are defined as “major” – defined as river basins with a floor area of over 1,400 square kilometers WATER RESOURCES ENGINEERING However, some regions are more blessed than others. For example, Water Resource Region 10 – Northern Mindanao – has about 31 million cubic meters (MCM) vs. Region 7 – Central Visayas – with only a little under 3 MCM. WATER RESOURCES ENGINEERING The Philippine water sector must find a way to manage its water resources most efficiently and sustainably to avoid a worsening situation in future years. The narrative and figures above highlight a major issue of the country’s water resources that is, rising demand for water when supplies are limited or shrinking, leading to water scarcity. This imbalance is caused by a variety of factors: ✓ Population growth and economic development. ✓ Climate change. ✓ Groundwater over-abstraction ✓ Pollution ✓ Forest denudation ✓ Institutional/legal water resource management framework THE CASE OF WATER SECURITY 1. “The reliable availability of an acceptable quantity and quality of water for production, livelihoods and health, coupled with an acceptable level of risk to society of unpredictable water-related impacts.” 2. “The capacity of a population to safeguard sustainable access to adequate quantities of acceptable quality water for sustaining livelihoods, human well-being, and socioeconomic development, for ensuring protection against water-borne pollution and water-related disasters, and for preserving ecosystems in a climate of peace and political stability.” THE CASE OF WATER SECURITY In operationalizing this definition, ADB defined water security along five measurable key dimensions as follows: 1. Household Water Security 2. Economic Water Security 3. Urban Water Security 4.Environmental Water Security 5. Resilience to Water-Related Disasters In this study, the Philippines ranked 33rd out of 48 countries, scoring poorly across all key dimensions. On a scale of 1-5, where 5 represents the highest level of water security, the Philippines only garnered a rating of 2. Parsing the data, much of the water insecurity seems to be driven by the available data, which paints a sorry state of the water sector, particularly in the area of municipal water supply. THE CASE OF WATER SECURITY In operationalizing this definition, ADB defined water security along five measurable key dimensions as follows: 1. Household Water Security 2.Economic Water Security 3.Urban Water Security 4.Environmental Water Security 5.Resilience to Water-Related Disasters HYDROLOGY Hydrology ✓ the science of water ✓ is a multidisciplinary subject that deals with the occurrence, circulation, storage, and distribution of surface and ground water on the earth (Bedient et al, 2013; Subramanya, 2008) Engineering Hydrology ✓ deals with (i) estimation of water resources, (ii) the study of processes such as precipitation, runoff, evapotranspiration and their interaction and (iii) the study of problems such as floods and droughts, and strategies to combat them (Subramanya, 2008).