GIS, or geographic information system, is a powerful tool for civil engineering design, especially for projects that involve water resources. In this article, you will learn how to use GIS to perform hydrological analysis for a new dam project, which is essential for estimating the water supply, demand, and quality in the area.
Hydrological analysis is the study of the movement, distribution, and quality of water in a watershed, which is the area of land that drains into a common water body. Hydrological analysis can help you determine the feasibility, design, and impact of a new dam project, as well as the potential risks and benefits for the environment and society. Hydrological analysis involves collecting and processing data on various aspects of the water cycle, such as precipitation, evaporation, runoff, infiltration, groundwater, streamflow, and water quality.
GIS can provide a spatial framework for storing, managing, analyzing, and visualizing data to help with hydrological analysis. It can also integrate data from different sources and scales, such as satellite imagery, topographic maps, hydrographic surveys, meteorological stations, and field measurements. With GIS, you can perform watershed delineation to define the boundaries and characteristics of the watershed. Additionally, it can be used for hydrological modeling by simulating the water balance and flow in the watershed with mathematical equations that represent physical processes. Furthermore, GIS can be used for hydrological assessment to evaluate the impacts and implications of a dam project on water availability, demand, quality, downstream ecosystems, and communities. It can also be used to calibrate and validate models with observed data and run scenarios with different inputs and parameters.
Nowadays we have so much free, publicly available data. This is a stark contrast to earlier in my career - we would have to email individual people from various authorities, who would then extract a very small amount of data around our site location, package it up in an almost useless format and charge $190 for the trouble! And that's if we were lucky... most of the time we just simply couldn't obtain useful data. Now we can download free LIDAR + access Council planning overlays + infrastructure information + access current rainfall data all in the comfort of our desk?? We have access to FREE GIS software, where we can then combine, analyse and utilise this data to undertake our civil engineering design??
Carrying out hydrological analysis with GIS involves a range of steps, depending on the scope, objectives, and data availability of your project. Generally, you need to collect and prepare data, such as spatial and temporal information on watershed features, climate, hydrology, and dam design. You must also check the quality, accuracy, and consistency of the data before converting them into compatible formats and coordinate systems for GIS. To process and manipulate the data, you need to use GIS to create digital elevation models, extract drainage networks, calculate watershed parameters, and apply hydrological models. Additionally, you need to use GIS for statistical and spatial analysis by calculating descriptive and inferential statistics, creating maps and charts, and performing spatial interpolation and extrapolation. To interpret and communicate the results of your analysis, you must use GIS to identify key findings, trends, patterns, compare scenarios and alternatives, and assess uncertainties and limitations. Finally, you need to use GIS to present the results in a clear manner by creating reports, tables, graphs, or maps.
Agree with others' comments - we need engineering judgement at all stages?? Stormwater, hydrology and hydraulics can be very subjective at times so we need to ensure a suitably qualified person (RPEQ, CPEng etc.) is managing and reviewing the design at all times.
Thanks I agree, but one also needs to apply human engineering judgement intelligence to assess whether AI generated solutions make sense or not, and are not just arrived at by pushing a button.
GIS for hydrological analysis can offer several advantages, such as improving comprehension of watershed dynamics and the impacts of dam projects. It can also enhance decision-making and problem-solving, as well as increase efficiency and productivity. Furthermore, GIS can reduce costs and errors while supporting collaboration and communication with other stakeholders.
Using GIS for hydrological analysis can also present some challenges, such as locating and obtaining reliable and relevant data, dealing with data gaps and inconsistencies, choosing and applying the right methods and models, managing large and complex data sets, as well as addressing ethical and legal issues.
Communication plays an integral part here too - talk about your interpretations, analysis, engineering solutions with your peers. You need different perspectives and experiences to help formulate a robust and complete design.