Calibration of Rainfall-Runoff Models
Total Page:16
File Type:pdf, Size:1020Kb
ET&P Srl ET&P Srl Environmental Tecnologies and Products Via Don Bedetti, 20 40129 – Bologna Tel.: (+39) 051 6389099 Fax: (+39) 051 6389100 EMail: [email protected] MUSIC – Multiple-Sensor Precipitation Measurements, Integration, Calibration and Flood Forecasting A Project supported by the European Commission under Contract No EVK1-CT-2000-00058 Published is here the Deliverable 9.1 titled Calibration of rainfall-runoff models By: Michele Marsigli, Francesca Todini, Tommaso Diomede, Zhiyu Liu, Rosa Vignoli ET&P Srl resulting from WP 9 Integration with the real-time flood forecasting system Contents Contents ..................................................................................................................... 2 1 Application of the TOPKAPI Model in the Arno River Basin ................................ 3 1.1 Characteristics of the Arno River Basin............................................................ 3 1.1.1 General description of the Arno River basin.............................................. 3 1.1.2 Topography............................................................................................... 4 1.1.3 Type and properties of soil........................................................................ 5 1.1.4 Vegetation and land .................................................................................. 6 1.2 Data preparation for the application of the TOPKAPI model ............................ 7 1.2.1 DEM application........................................................................................ 7 1.2.2 Hydro-meteorological data........................................................................ 8 1.2.3 Evapotranspiration .................................................................................. 11 1.3 Calibration of the TOPKAPI model................................................................. 18 1.3.1 Calibration parameters............................................................................ 18 1.3.2 Graphical calibration results on Upper Arno basin for 1992.................... 20 1.3.3 Graphical calibration results on Arno basin for 2000............................... 23 1.3.4 Statistical tests........................................................................................ 26 1.3.5 Considerations on calibration.................................................................. 28 1.4 Conclusions.................................................................................................... 28 2 Application of the TOPKAPI Model in Reno River Basin ................................... 29 2.1 Characteristics of the Reno river basin .......................................................... 29 2.1.1 General description of the Reno River basin........................................... 29 2.1.2 Topography............................................................................................. 31 2.1.3 Type and properties of soil...................................................................... 34 2.1.4 Land use................................................................................................. 35 2.2 Data preparation for the application of the Topkapi model............................. 37 2.2.1 Applications to DEM................................................................................ 37 2.2.2 Hydro-meteorological data...................................................................... 37 2.2.3 Evapotranspiration .................................................................................. 40 2.3 Calibration of the TOPKAPI model................................................................. 41 2.3.1 Calibration parameters............................................................................ 41 2.3.2 Graphical results of the calibration.......................................................... 44 2.3.3 Statistical Tests....................................................................................... 53 2.4 Validation of the model................................................................................... 54 2.5 Conclusions.................................................................................................... 60 MUSIC · Deliverable 9.1 · 6th Mar. 2002 Page 2 1 · Application of the TOPKAPI Model in Arno River Basin 1 Application of the TOPKAPI Model in the Arno River Basin 1.1 Characteristics of the Arno River Basin 1.1.1 General description of the Arno River basin The Arno River basin (Fig. 1.1) has the surface area of 8228 Km2. The river originates from the mountain Falterona (1654m a. s. l) situated in the northern border of Casentino. It initially starts in Northeast-Southwest for about 60 km in the Casentino (883 Km2), then it receives the water from the Chiana (1356 Km2) and debouches to the Valdarno Superiore (1005 Km2). The river flows in the direction of Southwest-Northeast and arrives at the confluence with the Sieve River (836 Km2), then it flows in East-West to the mouth of the river, in the course the Arno River receives some major tributaries as Greve River, Pesa Sream, Elsa River and Era River on the left side, and Bisenzio River, Ombrone River on the right side. The watercourse of the river has a total length of approximately 245 km. The bed slope of the Arno River varies from 0.14% in the stretch of Laterina-Nave di Rosano to 0.035% in the stretch of Florence-Pisa (Fig. 1.1). In the low-lying area of the Arno River basin, the width of the channel section has the order of 100~150 m in general. Bisenzio Fornacina Sieve Fornacina Padule Ombrone Fucecchio Pistoiese Pesa Casentino Pesa Greve Subbiano Valdarno Superiore Era Laterina S. Giovanni Ferrovia Elsa Chiana Firenze Nave di Rosano Figure 1.1 Arno river basin, sub-basins and water level stations MUSIC · Deliverable 9.1 · 6th Mar. 2002 Page 3 1 · Application of the TOPKAPI Model in Arno River Basin 1.1.2 Topography The Arno River basin has the surface area of 8228 Km2, 55% of which has an elevation lower than 300 m a.s.l., 30.4% is located between 300 and 600 m a.s.l., 9.8% has an elevation between 600 and 900 m a.s.l., and 4.5% has an elevation higher than 900 m a.s.l.. The major altitudes are found in the montains of Falterona and Pratomagno in the Casentino. The mean elevation in the whole river basin is 292 m a.s. l.. A digital elevation model (DEM) data file is available in the Arno River basin on the basis of 100x100 m cells. This study, uses a DEM with a gird size of 1km×1km derived from the previous one (see Fig.1.2). The area and the average elevation for major sub-basins are listed in Table 1.1. The local climatic conditions produce the highest flooding risk in the period from September to January in which the south-west winds dominate. Figure 1.2 DEM map for the Arno River basin (gird size 1km×1km) Basin Sieve Casentino Chiana Valdarno Greve Ombrone Bisenzio Pesa Elsa Era Name Superiore Pistoiese Area (km2) 836 883 1356 1005 294 486 304 327 856 587 Average Elevation 388 479 226 200 708 234 363 99 380 119 (m a.s.l.) Table 1.1 Topographic information of major subbasins in the Arno River basin MUSIC · Deliverable 9.1 · 6th Mar. 2002 Page 4 1 · Application of the TOPKAPI Model in Arno River Basin 1.1.3 Type and properties of soil A soil map of the Arno River basin, created by Milan Polytechnic on the basis of the SCS classification (U.S. Dept. Agric., Soil Conservation Service, 1972), was made available for this project in Arcview format (Fig. 1.3 and Tab. 1.2). The entire basin is divided into four classes; this schematisation is not entirely satisfactory, as will be described in the sequel, but it was the only one available. As shown in Table 1.2, the soil most present in the basin (almost 58% of the total area) is type C. This means that more than half of the soils have the following hydrologic characteristics: thin- bedded, with moderately high potential runoff, and containing a considerable quantity of argillaceous and colloidal materials; they have low infiltration and saturation capacity. In addition, the soils tend to be thin-bedded with low permeability in mountain areas, whereas they are thick and have medium-high permeability in the valleys. Figure 1.3 Hydrological classes of soil for the Arno river basin Hydrologic Percentage No. type of soil DESCRIPTION (%) (S.C.S/C.N.) 1 A With scarce potentiality of runoff. Contains deep sands with very scarce lime and clay, and deep gravel of high permeability. 18.5 2 B With moderately low potentiality of runoff. Contains the major part of the sandy soil that is less deep than the one in the group A, but 20.1 the group as a whole keeps high capacity of infiltration even when saturated. 3 C With moderately high potentiality of runoff. Contains the thin soils which contain considerable quantity of clay and colloidal, while 57.9 less than group D. The group has scarce capacity of infiltration when saturated. 4 D With middle high potentiality of runoff. Contains the major part of the clay soil with high capacity of expanding , but also the thin 0.965 soils almost impermeability nearby the surface. Table 1.2 Legend of pedological data (soil hydrologic types) MUSIC · Deliverable 9.1 · 6th Mar. 2002 Page 5 1 · Application of the TOPKAPI Model in Arno River Basin 1.1.4 Vegetation and land The land use map was derived from the CORINE mapping, produced by the European Union. Fig. 1.4 shows the distribution of land use in the Arno River basin, and Tab. 1.3 describes its individual characteristics and gives the percentage of area for each type present in the basin. It