Finding Potential Sites for Small-Scale Hydro Power in Uganda: a ...

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The first step when performing the quality assessment of our interpolated DEMs was tocompare derived contours from the three different resolutions with the original contours.As can be seen in Figure 5.5 the degree of agreement, regarding terrain structure,increases with increased resolution.(a) (b) (c)Figure 5.5 Derived contours from DEMs in different resolutions. a) 100 meters, b) 30 meters andc) 10 meters. Red lines representing original contours and black lines the derived contours fromthe interpolated DEM.The second step in the quality assessment was to visually inspect shaded relief images ofthe interpolated DEMs. This step made it possible to locate a number of anomalies thatshowed up as very contrasting areas. It was possible to detect both geometricaldisplacement and attribute errors. An example of geometrical displacement is verticaledge errors, which can be seen in Figure 5.6 below. These errors were edited bycorrecting the attribute table and the interpolation repeated until a satisfying result wasobtained. A certain degree of terracing can also be noticed along the slopes in the figure.(a)Figure 5.6 Shaded relief of DEM with 10-meter resolution. a) Showing digitised errors leading tovertical edge error problems and (b) same area after editing of input data.(b)50
To evaluate accuracy of the absolute elevation of the DEMs, we calculated the RMS-at four different reference locations. The result, which can be seen in Table 5.1errorsshows that the lowest RMS-errors occurs at steep areas in the DEM with 10-meterresolution. At flat areas the RMS-error are within the same range of values, regardless ofresolution. There is a noticeable increase in RMS-error with increased cell-size in steepareas.Table 5.1 RMS-error for the DEM at the references lines, in three different resolutions.Resolution Flat 1 Flat 2 Steep 1 Steep 2 Mean RMS100 meter 14.64488 14.32897 29.07937 43.40787 25.3652730 meter 12.84792 14.78252 16.47471 23.72902 16.9585410 meter 12.83892 15.45371 7.22123 7.36828 10.72054The outcome of the quality assessment points to that the 10-meter resolution DEM is agood choice for our analysis. It has the highest degree of accuracy regarding both terrainstructure and absolute elevation. Figure 5.7 shows the digital elevation model over ourstudy area.Figure 5.7 A 3-D image of the DEM with 10-meter resolution over the districts Kisoro and Kabale.A five-time vertical exaggeration factor has been used to highlight the shapes of the landscape.Lighter areas represent high elevation and darker low.5.2.2 AlgorithmThe first unprocessed output data, for the entire study area, is produced by the algorithmwithin a couple of minutes. A selection from the output data can be seen in Figure 5.8a.A first look at the output gives a rather vague impression of what the result actuallyrepresent, but when applying the contours (see Figure 5.8b) the potential sites appear51
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Seminar series nr 121Finding Potent
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AbstractOver 2 billion people, most
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AcknowledgmentsFirst of all, we wou
Page 12 and 13: 5 Result ..........................
Page 14 and 15: For the specific case of Uganda, a
Page 17 and 18: 2 Study AreaThe main reason for us
Page 19 and 20: In the 1960’s Uganda was one of t
Page 21 and 22: 2.1.3 TopographyMost of Uganda is s
Page 23: Figure 2.4 The highest volcano in K
Page 26 and 27: e able to manually write the data,
Page 28 and 29: Depending on the appearance of the
Page 30 and 31: o Then the water flows from the for
Page 32 and 33: and generator is 65% and 80% effici
Page 34 and 35: Table 3.2 Capacity and production o
Page 36 and 37: Table 3.5 Small-scale hydropower ca
Page 38 and 39: technology was supplied to an area
Page 40 and 41: component to all of these issues, g
Page 42 and 43: The Rural Electrification project t
Page 44 and 45: The closer the interviewer is to th
Page 46 and 47: Over this area we bought the follow
Page 48 and 49: The primary erosive force determini
Page 50 and 51: There are a set of tolerances used
Page 52 and 53: ivers are seasonal, since the hydro
Page 54 and 55: (a) (b) (c)Figure 4.8 An example sh
Page 56 and 57: 4.2.6 Post Processing of Output Dat
Page 58 and 59: A = ( b ⋅ h)2(4.3)Where A equals
Page 60 and 61: elinquish because of too expensive
Page 64 and 65: more obvious in their geographic co
Page 66 and 67: By using a smaller area it is possi
Page 68 and 69: 5.3 Summary of Resultso The general
Page 70 and 71: projects are supposed to be finance
Page 72 and 73: Sinks are a reoccurring problem whe
Page 74 and 75: UTM Zone 36N projection. The study
Page 76 and 77: As described in chapter 3.3.3 all r
Page 78 and 79: and if good financing possibilities
Page 80 and 81: Hutchinson M. F., Dowling T. I., 19
Page 83 and 84: 9 Appendix9.1 Interview: Rural Elec
Page 85 and 86: 9.3 Digital DataAll data layers are
Page 87 and 88: Frame creationThis is made in order
Page 89 and 90: time2=clock;%starts timer on clock
Page 91 and 92: next(1,2)=(y-1);cell_height=(highes
Page 93 and 94: endendif height>=20;%if the accumul
Page 95: Site 16 (147486,78619)Site 20 (1560
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