Tutorials Data Himalaya
The tutorial is prepared to use the J2000 hydrological model for hydrological system analysis of a river catchment. A test catchment and dataset of the Dudh Kosi river basin has been provided along with the tutorial. The Dudh Kosi river basin was used for the hydrological system analysis by using the J2000 hydrological model as a part of the PhD research (Nepal, 2012). The information provided here is largely based on this study. PhD Thesis. The motivation, objectives and methodological apporach and the rational of using the J2000 model in the Dudh Kosi river basin are also presented. The users can use the test data to get familiar with the model application. At the same time, users can prepare their own dataset to understand the hydrological system dynamics of any river basin by following this tutorial.
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Who can use the tutorial
The tutorial is prepared in such a way that the J2000 hydrological model can be used independently without any techtical support from model developers. Therefore, it can be used by students, model developers and researchers for the hydrological system analysis of a catchment. The tutorial should be read in conjunction with other sub-tutorials which has been mentioned in different part of this tutorial. Additionally, the tutorial is supplied with test dataset of the Dudh Kosi river basin (Nepal, 2012) which users can use to get familiar with the different aspects of the J2000 model. Similarly, users can also create their own dataset of the catchment of interest to run the model.
Description of the test dataset
The tutorial is accompained by the test dataset of the Dudh Kosi river basin. This hydro-meteorological data were provided by the Department of Hydrology and Meteorology (DHM), Government of Nepal. The DHM has provided permission to use the data along with the tutorial. The users are expected to use the tutorial along with the test data to understand different aspects of the J2000 modelling system and also aim to prepare their own dataset to run the model.
Motivation
This is the motivation of the study.
Study area
This is the Study area, Dudh Kosi river basin.
Objectives and methods
The main objectives of the
Preparation of dataset
Model parameter files
The requirement of the data to run the J2000 hydrological model is discussed in detail which is a pre-requisite to run the model. Two types of data are required i) model parameter files and ii) meteorological input data. The first one is prepared and quantified inside the GIS environment and known as model parameter files. The parameter files and their values are static in the modelling application.
Users have to prepare all the input data (i.e. soil, land cover, geology, DEM) in raster format with certain resolution. While delineating HRUs, all the input data has to be provided in a same resolution. The resolution of the dataset mainly controls the number of HRUs to be formed without loosing the heterogeneity of a catchment. Therefore, the resolution of input data depends upon a catchment to be modelled. If the catchment is small (e.g. 600 km²), the resolution between 30-90 is suitable depending upon the resolution of the available dataset. Similarly, for meso-scale catchment (e.g. 4000 km²), resolution between 250-500 m is suitable.
The detailed descriptions to derive the parameter files are provided below:
Soil parameter file
The detailed information required for the soil parameter file is provided in Table below.
| Parameter | Description |
|---|---|
| SID | soil type ID |
| depth | depth of soil |
| kf_min | minimum permeability coefficient |
| depth_min | depth of the horizon above the horizon with the smallest permeability coefficient |
| kf_max | maximum permeability coefficient |
| cap_rise | Boolean variable, that allows (1) or restricts (0) capillary ascension |
| aircap | air capacity (equivalent to large pore storages (LPS)) |
| fc_sum | useable field capacity (equivalent to middle pore storages (MPS)) |
| fc_1 ...22 | useable field capacity per decimeter of profile depth |
The soil parameter file is one of the important parameter files which needs a range of information as shown in Table above to produce a comprehensive characterization regarding water holding capacity of different soil types. For this, the texture information of soil types of different soil horizons are required. A detailed description of how to produce soil parameter file is provided here:
How to prepare soil parameter file
Land cover parameter file
The land-use parameter file requires information about the land-use and land-cover of a catchment which controls the different aspects of hydrology. Such information can be derived from literature where the spatial information about the land-use and land-cover is provided. Alternatively, such information can be estimated by using remote sensing images and subsequent classification. The J2000 hydrological model requires major classification of land-use and land-cover which affects the hydrological dynamcis.
How to prepare land cover parameter file
Hydro-geological parameter file
The information required for the Hydro-geological parameter file are provided below:
- hgeo.par
| parameter | description |
|---|---|
| GID | hydrogeology ID |
| RG1_max | maximum storage capacity of the upper ground-water reservoir |
| RG2_max | maximum storage capacity of the lower ground-water reservoir |
| RG1_k | storage coefficient of the upper ground-water reservoir |
| RG2_k | storage coefficient of the lower ground-water reservoir |
The storage capacity of upper (RG1) and lower (RG2) grounwater storage can be estimated by analyzing geological information of the area. The storage capacity is normally controlled by the geological formation, rock types, origin and nature of rocks and permeability. This value only indicates the maximum water stroage capacity (RG1_max and RG2_max) of each storage type. The stroage coefficient values (RG1_k and RG2_k) are used as a general recession co-efficient of two stroage. The recession is further controlled by a flexible calibration parameter within the model.
HRUs/Reach parameter file
Hydrological Response Units (HRUs) are the modelling entities for the J2000 hydrological model. HRUs are 'saptial model entities which are distributed, heterogeneous structured entities having a common climate,land-use, soil, and geology controlling their hydrological dynamics'(Flugel 1995). The areas which comprise similar properties such as topography (slope, aspects), land-use, soil and geology, and behaves similarly in their hydrological response, are merged together to develop a HRU. The variation of the hydrological process dynamics within the HRU should be relatively small compared with the dynamics in a different HRU (Flugel 1995).
The processing of delineating HRUs are described in the following tutorial.
The delineation of HRUs process provide HRU and Reach parameter file at the end.
- hur parameter file
- hrus.par
Parameters of the given Hydrological Response Units (HRUs)
| parameter | description |
|---|---|
| ID | HRU ID |
| x | easting of the centroid point |
| y | northing of the centroid point |
| elevation | mean elevation |
| area | area |
| type | drainage type: HRU drains in HRU (2), HRU drains in channel part (3) |
| to_poly | ID of the underlying HRU |
| to_reach | ID of the adjacent channel part |
| slope | slope |
| aspect | aspect |
| flowlength | flow length |
| soilID | ID soil class |
| landuseID | ID land use class |
| hgeoID | ID hydrogeologic class |
Meteorological input data
The J2000 hydrological model requires the input of the hydro-meteorological data as provided in Table below:
