UNIVERSITY OF KURDISTAN – HAWLER
ANALYSING STORAGE OF DAM BY USING GIS
DRAFT OF THE SEMI FINAL PROJECT
SRUSHT AHMED SHASWAR- 1100237
The aim of this study is to analyze and investigate the storage of water in a reservoir by using remote sensing date and Geographical Information System (GIS). Because Traditional way of estimating reservoir storage is quite costly, laborious and time consuming, while using the latest technology of remote sensing and GIS make it very effective in terms of cost and time.
TABLE OF CONTENT
1. Introduction …………………………………...3.
1.1 General backgrounds………………………….3.
1.1.1 Dams………………………………… ……3.
1.1.2 Dams in Kurdistan region………………….7.
1.2 Theoretical backgrounds…………… …… ….10.
1.2.1 Geographical information system………….10.
1.2.2 Arc map………… ………………………..9.
1.2.3 Hydrology tools……………………… ……9.
1.2.4 Digital elevation system …………………..10.
1.3 Statement of the problem …………………….10.
1.4 Objective of the study ………………………..10.
2.1 literature review,………………………..11.
3.1 study area …………………………………14.
3.2 data collection………………………………16
3.2.1 Topographic and land map ……………….16
3.2.2 Feasibility report ………………………...17
3.2.3 Hydrology data…………………………18.
3.2.4 Soil texture …………………… ….……18
3.3 methods for data analysis………………..19
1.1: General background
A dam is hydraulic structure designed as a barrier across a river to impound the flow of water and create a reservoir. The dams are not only constructed to suppress floods but also it’s a key structure for many other activities such as flood control, irrigation, hydroelectric power generation, recreation, navigation, , industrial use, water supply, , and other important economic benefits. (Sawuyame. T,2005)
There are several type of Dams, depending on the function and the structure of the dam (Damsafety.org, 2016).
Depending on function it can be classified as
• Storage dams: this type of dam is designed to store water during the rainy season and use it in the dry season. In a way that the water is stored by many small dams when there is a large flow in the river during wet seasons and then it can be used in summer.
• Diversion dams A diversion dam is designed to divert water from the river into an off taking canal. Since the river provide enough pressure for pushing water into the canals or other conveyance systems. This type is usually has a smaller storage space.
• Detention dams: Detention dams are designed for flood control, which reduces the flow of floods by storing some of the flood water on its downstream. Then the water that kept in the reservoir is gradually discharged.
In order to protect the downstream areas from flood, after releasing the water, the velocity and the pressure of the water should be controlled based on the capacity of the channel downstream of the dam that takes the water.
• Debris dams: A debris dam is designed as a screen which is used to retain the wreckage from the river water and clean them from debris such as sand, gravel, wood and etc. thus The water that pass through debris dam considered to be clear.
• Coffer dams: It is a temporary dam; since the dams are usually constructed across a river so it's difficult to store all the river water unless constructing a temporary dam. Coffer dams usually built on the upstream of the main dam to divert and exclude water into a diversion channel during the construction of the dam.
Depending on structure and construction, dams can be classified as 184.108.40.206:
Gravity Dams: A gravity dam is a very big sized dam. They are constructed to store and hold large capacity of water. Concrete or stone masonry are the main component used in building the gravity dam. Since gravity dams must depend on their own weight to hold back water, so it is necessary that they are manufactured on a solid foundation of bedrock and using concrete for the wall to support the dam from any hazardous accident and it can withstand horizontally of the water pushing against it.
This type of dam is suitable for blocking rivers in wide valleys or narrow ways.
Earth Dams: An earth dam is called from which it's constructed on earth. It's made on the successive layers of earth's soil. Its constructed from the most impermeable materials in order to form unbreakable foundation with a very strong sides (upstream and downstream) so that the soil has a shear strength that resists the forces exerted upon it and the height of the dam rely on it as well.
This type of dam is usually built in wide valleys having flat slopes.
Rockfill Dams: A rockfill dam is constructed mainly of rock rubbles and boulders of large size. It's known by placing an impervious membrane on the rockfill on the upstream side in order to decrease the seepage through the dam. They used to use steel and timber membrane in rockfill dam but now the membrane that is used is usually made of concrete (cement or asphaltic).
Arch Dams: arch dam is the only dam that curves and convexes in the same structure. It is curved in plan while its convexity towards the upstream side. It's called an arch dam since it transmits the water pressure and other forces by arch action.
An arch dam is suitable for narrow canyons with strong edges which has ability to resist the thrust produced by the arch action.
Steel Dams: A steel dam is mainly made up from steel structure, the upstream face is covered with a steel skin plate on its. There are two types of Steel dams:
(i) Direct-strutted steel dams
(ii) Cantilever type steel dams.
Steel dams are occasionally used as temporary coffer dams during the construction of the main dams.
Timber Dams: timber dam is made of wood, such as pine and fir. Timber dams are made for small heads from (2-4 m) while in many some cases it's made for higher head (4-8 m) and usually have sluices to clean the water.
According to the design there are two type of timber dam:
(i) pile, crib
(iii) Buttressed dams
Figure (1.1) shows the types of dams according to structures
figure (1.1) the types of dam according to structure (Civil Engineering Blog, 2015)
Dams in Kurdistan region 1.1.2
"Water is life" water is the most necessary and the most essential material for every single creature on earth. Since water is vital to life and because of its unique property makes life possible and easier on earth.
Water availability in Kurdistan Region is highly variable. It's changing due to annual rainfall and geography. As its recognized Kurdistan has a Mediterranean climate known by its rainy and cold winter, and it's dry and hot summer. The Rainy season start from October till April, whereas the rest of the months are almost dry and hot. Based on the average annual rainfall of Kurdistan region, it is divided into three areas. (Ministry of agriculture and water resources/ Kurdistan region government 2012)
the assured rainfall area where the average of annual rainfall is over 500 mm, while the semi assured rainfall areas are where the annual average is lesser than 500mm and higher than 350 and the area where the average annual rainfall is less than 350mm. (Regional Development Strategy for Kurdistan Region 2013-2017 2012)
Not only rainfall but Kurdistan is also wealthy with ground water and surface water. There are numerous of rivers, wells and springs. Digging well in Kurdistan is one of the most common phenomena for acquiring water.
There are also several rivers in Kurdistan, sourced from Iran and Turkey while after passing through different areas of the Kurdistan Region, continue to flow to the other parts of Iraq. (Table 1.1) shows the rivers passing through Kurdistan region.
Table 1.1 the amount and the length of the rivers in Kurdistan region (Source: MAWR/KRG)
However, beside rich amounts of water including surface water, ground water and the great amount of rainwater and snow falling on main water basins just a few hundred meters away from the rivers in the region, drought and climate changing threaten thousands of the farmlands and farmers, livelihoods. In some years and some places, Kurdistan suffers from many water problems such as poor rainfall, water shortage and lack of ground water in some places. Professor Baban, (Minister of Agriculture and Water Resources), outlined plans and stepped good procedures to achieve water sufficiency for the people of Kurdistan in order to resist the coming global environmental factors such as the climate change and water shortages. Hence there will be no sufficient water for irrigation, agriculture, drinking and etc…
For this reason KRG proposed some dam construction in order to reduce the problems.
Currently there are 8 dams in Kurdistan that have been completed and have a capacity for storing the water. Dukan dam , darbandixan dam and duhok dam are the three main dams in Kurdistan region.(figure 1.2) shows the major dams in Kurdistan. in addition to 13 other dams that are under construction now as well as many other large dam projects in government which are proposed to construct (Directorate of Dams).
If the region's water resources used effectively they can advance the agriculture sector, tourism sector and the region can achieve to a self-independence country in many terms of economy.
1.2 Theoretical background
1.2.1 Geographic Information System (GIS)
GIS is a new technique which has ability to provide powerful and cost-effective tools for managing, re-designing and processing data and maps for water resources and reservoirs in particular. (Estes.C ,2014)
Nowadays by using GIS the hydrologist and the researchers are able to get better access to high quality hydrologic data. Taking data and calculating by using GIS is easier and more accurate for finding storage volume and catchment areas. Since it’s a computerized system intended to capture, manipulate and analyze all types of geographical data. There are several types GIS and each is specialized and support different types of systems and manage different transformations between the types. ArcGIS has five applications (ArcGlobe, ArcSCene, ArcToolbox, ArcCatalog and ArcMap (Rolf, 2001).
1.2.2ArcMap It is an application of GIS software that used mainly to edit, view, and analyze geospatial dataset it is also used to create maps and cartographic representations of GIS data (Saephan 2005).
1.2.3 Hydrology Tool
The Hydrology tools are used to understand the shape of the earth's surface. It clarifies all the hydrologic function. It derives several data and concepts regarding drainage system and surface processes. Its presents the digital elevation model (DEM) and generate data to fill, flow direction, flow accumulation, streams, stream segments, watersheds and basin (Weizhe.A, 2007)
1.2.4. Digital Elevation Model (DEM)
DEM provides a digital image of a section of earth's surface topography in xyz coordinates or two dimensional surfaces. It represents height information above some arbitrary datum in the landscape in an ordered arrangement of numbers. (Meijerink et al., 1994). The quality of the DEM in ArcGIS is recognized by the size of the pixels,
1.3: Statement of the Problem
Generally to find the storage of a reservoir or any other hydrological characteristics, to start with any engineering constructions, engineers do surveying to obtain stations data by using instrument to the find the total station of that region to be able to draw the contour line of that area so that the location of the suitable elevation to construct the dam is estimated. This procedure consume too much time and effort while by using GIS, the engineers are able to obtain the data easier and more accurate.
1.4: Objectives of study
In this research we aim
• To assess the storage and the capacity of shiwashook reservoir by using GIS and remote sensing. The suitable location of the dam
• To give us more accurate results and less time consuming.
• To evaluate alternatives for enhancing storage with small modification in dam height
2.1 Literature review
• "GEOGRAPHIC INFORMATION SYSTEM"
Geographic Information Systems (GIS) powerful technique Composed of many collected data about a desired basin in order make the best engineering decisions including highway planning, forecasting environmental impacts and districting mapping.
Estes (2014) classified the types of GIS and he state that each type of GIS is specialized to a specific function such as the GIS team imbedded in an agency of topographic mapping or it can be used for solving business problems. As well as it can be used for agriculture and health issues
In conclusion we can sum up to that GIS is a new technique which has ability to provide powerful and cost-effective tools for managing, re-designing and processing data and maps for every environmental impacts, water resources and reservoirs in particular.
• "The Study of GIS-Based Hydrological Model in Highway Environmental Assessment"
Based on GIS Weizhe (2007) developed a model for giving detailed data about runoff and rainfall. The model is using the Watershed Modeling System (WMS) to create the hydrology activities along the stream system draining selected watersheds. Also hydrodynamic model based on GIS techniques has been developed since the flows that are measured at the gauging station are not enough to give full view information of the river's conditions.
So by using the new technique it's able to investigate and map out the downstream impact of the river. (Weizhe.A, 2007)
• "Small Reservoir Capacity Estimation"
It's possible to measure the depth of the water in a reservoir with the coordinates in order to calculate the area and the capacity of the desired reservoir by using geographical information system based on information acquired from the field and from satellite images. Then the result data was compared to create a connection between surface area and storage capacity of small reservoirs. (Sawunyama. M, Senzanje. A, Mhizha. A, 2006)
• "Estimation of small reservoir storage capacity using GIS"
These days the small reservoirs are constructed for many reasons. It can be used to store runoff water against flooding In addition to domestic use, livestock watering, and irrigation and fisheries enhancement.
For this purpose Tendai found that digital maps and the remote sensing are suitable to detect small reservoirs and accurately measure their surface areas. (S. Tendai , 2005) This method is developed to estimate physical characteristics and the hydrological data of the region.
Detailed information and every required data for constructing small reservoirs can be found by GIS and remote sensing without the need to carry out extensive field surveys.
We can conclude that the use of satellite images and the obtained small reservoir capacities have a significant effect in water resources planning and management.Since this system provides a device to calculate water available in small reservoirs and hence help the planners to have a clear image of water resource system in the river basin. (S. Tendai , 2005)
• "Modeling topographic potential for erosion and deposition using GIS"
In order to build a strong dam and construct a good reservoir the engineers should understand the nature of the topography of that region so that they will be familiar with the type of the soil and the geographical characteristics of that place. GIS give engineers another opportunity to find the type and the characteristics of the desired basin.(Mitasova.H ,2003)
According to Helena Mitasova Full integration of topographic analysis using GIS, together with 3D visualization show an effective valuation of various approaches to understand the landscape of the erosion and deposition risk assessment for the desired basin. So by using of satellite images we can find the topographic of the place without the need to carry out extensive field surveys.
• "Gis modules and distributed models of the watershed"
In 2003 Quimpo developed a quasi-distributed GIS-based hydrologic model (QD-GISHydro), the model contains numerous different modules such as computing the runoff time series at the watershed outlet and processing information describing the spatial disparity of watershed properties.
• "Regional scale ﬂood modeling using NEXRAD rainfall, GIS"
Knebl (2002) concluded that the small reservoirs are constructed usually based on the rainfall and the runoff so the engineers should be familiars with the hydrological characteristics of the site. The (GIS) model has the capability to achieve all the hydrological data on a regional scale, as well as presenting the boundary conditions for local models. "The successful incorporation of the Map-to-Map technology at a regional scale demonstrates the versatility of this tool for ﬂood inundation studies at the city, county, and regional levels" M.R. Knebl , (2002)
• "Design flood estimation using GIS supported Geomorphic Instantaneous Unit Hydrograph approach"
Jain (2002) state that the Traditional techniques for designing flood estimation were using the historical rainfall-runoff data of that area in order to predict the following year's rainfall as well runoff. These techniques have been widely used for the estimation of design flood hydrograph at the sites of gauged catchment before the study of GIS.
Geographical Information System (GIS) supported the traditional way for the estimation of design flood. "GIS is a mathematical model that has been developed at the National Institute of Hydrology". SK Jain - 2000
Study area: Shiwashook dam 3.1
The dam in shiwashook village is one of the very important dams between the dams which are proposed to construct in Kurdistan. It is located in Kurdistan region at the north of Iraq which is situated in the province of Erbil city near koya township. It’s constructing for storing the seasonal water that runs off in it and also to prevent flooding during the wet season as well as irrigation in the dry seasons. An Extensive field mechanism was used in the area around Shiwashook village in order to find the suitable place for constructing the dam. As a result, the proposed dam decided to be constructed in the valley named Doli Shiwashook, which is regarded as a main valley in the area and its tributaries sourced from Eastern limb of Shiwashook anticline and runs in northwest- southeast direction. The dam site is located about 400 m west of the Shiwashook village, around the coordinates 458829 E, 3985158 N. ( figure 3.1) shows the location of shiwashook village .
Figure 3.1 tectonic subdivisions of Iraq by Buday (1980)
The catchment area of the reservoir of shiwashook dam is estimated to be 15.4 km2, most of this area is undulating area. Although the catchment area, is about 465m above mean sea level but it collect runoff water from areas of upper boundaries which are about 600m above mean sea level. Also it is included in the catchment area of the Lesser Zab so it receives runoff from numbers of small tributaries as well. (Figure 3.2) shows the catchment area of shiwashook dam (Feasibility report)
(Figure 3.2) shows the catchment area of shiwashook dam
The cover soil of the catchment area is almost mixed. At the north boundaries it is covered by big rocks, while at the middle of the catchment area covered by silty soil and at the bed of the stream covered with coarse materials. The lateral part of the catchment area is originated from thin bedded of grayish brown sandstone as well as siltstone, and clay stone while they are reddish brown color. (Figure 3.3) shows the beds of the lateral part of the dam.
(Figure 3.3) shows the beds of the lateral part of the dam.
Dam elevation is estimated to be 450m while the Dam height is about 20-25m. The dam is earth dam type and the stream bed level is 465-615m where as the stream width is 100m.
The capacity of the water in the shiwashook reservoir is estimated to be (1,100,000-1,400,000) cubic meter.
In order to have a clear view of the study we should collect the following data.
1. Topographic images and land use map 3.2.1
They are the main requirement order to be more familiar with the site location of the dam. Contour map for Shiwashook region had been obtained and carefully reviewed. By using GPS and satellite images
figure (3.4)Shiwashook Dam site obtained from Google earth image
Figure 3.5Topographic map showing dam location and catchment area.
3.2.2 Feasibility report
• Estimated catchment area: 15.4 km2.
• Dam elevation: 450
• Dam height: 20-25m
• Stream bed level: 465-615 m
• Stream width: 160-280 m
• Estimating for reservoir capacity in:
Dam 1: 1,100,000-1,400,000 cubic meter
3.2.3. Hydrological data
Hydrologic and climatic data of shiwashook/ koya have been obtained and classified from Metrological station in the region (Erbil and Koya). And by using the Rain fall and catchment area we can find the run off too.
Figure 3.6 shows the mean Annual Rainfall (mm) in Kurdistanregion
3.2.4 Soil texture
The catchment area of shiwashook dam site have been examined in order to obtain an overall understanding about the soil texture of the area and to determine the sediment yield, by sampling the soil in different part of the area.
3.3 Methods for Data Analysis:
GIS is a computerizing system or digitally process that converts analog data (hard copies of map) in to a soft copy of a digital data. By using 3D visualization and GIS model we will be able to create a complete image of our geographic data.
By Using DEMs it's able to determine the areas borders, the slop and the flow direction of the site location, In order to calculate water storage capacity of reservoirs. After an extensive surveying to determining the water yield in the location, and the amount water that can be stored in the location depending on the different crest height
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