Ministry of Irrigation Groundwater Resources Development Board Babarmahal, Kathmandu Inventory of Valleys in Nepal Main Report Team involved for the Study: DELL Surendra Raj Shrestha, Senior Divisional Hydrogeologist (Corresponding email: shree_surendraraj@yahoo.com) Surendra Shah, Hydrogeologist (Corresponding email: surendra_shah@hotmail.com) Table of Contents 1. Introduction .................................................................................................................................. 1 1.1 Background ............................................................................................................................... 1 1.2 Rationalization of the Study ............................................................................................... 2 1.3 Study Area ................................................................................................................................ 3 1.3.1 Topography ....................................................................................................................... 3 1.3.2 Drainage and River System........................................................................................ 4 1.3.3 Physiography and Geology ......................................................................................... 5 1.3.4 Climate ............................................................................................................................... 9 1.4 Objective and Scope of Works ........................................................................................ 10 1.5 Structure of the Report ...................................................................................................... 11 1.6 Limitation of the Study ...................................................................................................... 11 2. Approach and Methodology .................................................................................................. 13 2.1 General Approach ................................................................................................................. 13 2.2 Methodology ........................................................................................................................... 14 2.2.1 Literature review and Data Collection .................................................................. 14 2.2.2 Use of ArcGIS: Model builder .................................................................................. 14 2.3 3. Report Preparation ..................................................................................................................... 16 Valley: Definition and Terminology ................................................................................... 17 3.1 Definition of Valley ............................................................................................................... 17 3.2 Types of Valley ...................................................................................................................... 18 3.2.1 V and U Shaped Valley ............................................................................................. 18 3.2.2 Hanging Valley............................................................................................................... 18 3.2.3 Rift Valley ........................................................................................................................ 18 3.2.4 Open River Valley (Dale) ........................................................................................... 19 3.2.5 Tectonic Valley (Intermountain Basin) ................................................................ 19 4. Valley Inventory of Nepal...................................................................................................... 20 4.1 General Consideration ........................................................................................................ 20 4.2 Valley Inventory: Results .................................................................................................. 21 4.2.1 Page | i Mechi Zone...................................................................................................................... 23 Main Report 5. 4.2.2 Koshi Zone ...................................................................................................................... 24 4.2.3 Sagarmatha Zone......................................................................................................... 24 4.2.4 Janakpur Zone ............................................................................................................... 25 4.2.5 Bagmati Zone................................................................................................................. 26 4.2.6 Narayani Zone ............................................................................................................... 28 4.2.7 Gandali Zone .................................................................................................................. 30 4.2.8 Dhaulagiri Zone ............................................................................................................. 34 4.2.9 Lumbini Zone ................................................................................................................. 35 4.2.10 Rapti Zone ................................................................................................................... 37 4.2.11 Bheri Zone ................................................................................................................... 40 4.2.12 Karnali Zone ............................................................................................................... 43 4.2.13 Seti Zone ..................................................................................................................... 44 4.2.14 Mahakali Zone ........................................................................................................... 45 Results and Discussion ........................................................................................................... 46 LIST OF REFERENCES ......................................................................................................................... 48 Annex: District Wise Valley Inventory Map of Nepal List of Figures Figure Figure Figure Figure Figure 1-1: 1-2: 2-1: 2-2: 4-1: Major Drainage system of Nepal .............................................................................. 4 Physiographic Sub-division of Nepal ....................................................................... 6 View ArcGIS 9.3 Model Builder Window .............................................................. 15 Work Flow Chart for Valley Delineation ............................................................... 16 Map showing valleys of Nepal ................................................................................. 22 List of Tables Table 1-1: Summary of Characteristics of physiographic sub-division of Nepal ........... 6 Table 1-2: Seasonal rainfall distribution ..................................................................................... 10 Page | ii Main Report Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table 4-1: Valleys of Mechi Zone, Nepal .................................................................................... 23 4-2: Valleys of Koshi Zone, Nepal ..................................................................................... 24 4-3: Valleys of Sagarmatha Zone, Nepal ....................................................................... 24 4-4: Valleys of Janakpur Zone, Nepal.............................................................................. 25 4-5: Valleys of Bagmati Zone, Nepal ............................................................................... 27 4-6: Valleys of Narayani Zone, Nepal .............................................................................. 28 4-7: Valleys of Gandaki Zone, Nepal ............................................................................... 30 4-8: Valleys of Dhaulagiri Zone, Nepal ........................................................................... 34 4-9: Valleys of Lumbini Zone, Nepal ................................................................................ 35 4-10: Valleys of Rapti Zone, Nepal ................................................................................... 38 4-11: Valleys of Bheri Zone, Nepal ................................................................................... 40 4-12: Valleys of Karnali Zone, Nepal ............................................................................... 43 4-13: Valleys of Seti Zone, Nepal ..................................................................................... 44 4-14: Valleys of Mahakali Zone, Nepal............................................................................ 45 5-1: Results of Valley Inventory in Nepal ...................................................................... 46 Reference Annex: District Wise Valley Inventory Map of Nepal Page | iii Main Report 1. Introduction 1.1 Background Nepal is a small and landlocked country which extends from the highest peak in the world to the plains of the Terai. It lies between 80o – 88o E and 26o – 31o N, and occupies the central portion of the Himalayan chain between China and India with a land area of 147 181 km2 being 800 km from east to west, and from 144 km to 240 km north to south. The altitude varies from about 60 m amsl (Kechanakalan of Jhapa District in south) to 8848 m amsl (Mt. Everest in the north). It has different geological and geographical features. Nepal has distinct land use patterns as it is influenced by climatic variation, altitude and relief. Land use in the hills differs from that of the plains. The nature of settlement and landuse is determines by physiographic features like slope, river valleys, plains and ridges. The distribution of the population is unequal due to the diversity in land structure, climate, soil and available natural resources and means. Valleys and plains are the main locations for settlement, farming and trading due to availability of water and suitable toography. After the eradication of malaria in 1958 there has been a massive migration of people from the hills and mountains to the Terai and low lying river valleys. In this regard, valleys and plain areas plays major role for the agricultural, economic and social development of the country. Groundwater resources exploration and identification activities in Nepal started as early as 1967 with establishment of Groundwater Resource Development Board which was established in 1969. The main objectives of the GWRDB are: • To carry out Groundwater investigation, exploration and studies for irrigation, drinking water and other uses. • To establish data base and effective information system of groundwater resources of Nepal. Page | 1 Main Report • To suggest the government to carry out necessary policy, law, act, regulation about groundwater resources of Nepal. Groundwater Resources Development Board (GWRDB), located at Babarmahal, Kathmandu is responsible to carry out above mentioned activities through its 9 Branch Offices. Most of GWRDB investigation work is confined to ascertain groundwater potential in the Terai plains. At present, GWRDB is trying to extend its working area beyond Terai. Groundwater resources have been prominent source of water resources in Nepal. Due to diversity in its geology, geomorphology and physiography, groundwater resources occur in almost all natural settings. However, significant groundwater basins are located in the Tarai Plains and in some of the mid-hill valleys, such as Kathmandu and the Dang. 1.2 Rationalization of the Study Numerous formal and informal sources indicate that well drilling activity is on the rise even in the mid-hill valley region in Nepal. Urban canters developed in valley like Pokhara, Hetauda, Dharan and some agriculturally developed areas such as Panchkhal, Udaypur and others are some of those areas where private sector is already known to be extracting groundwater for various use purposes. The exact situation of groundwater extraction in these areas is however not known because there is no legal requirement or institutional mechanism to collect their information. For the past two decades or more, groundwater extraction, or rather overextraction has been known in Kathmandu valley. A public interest litigation was filed in the Supreme Court by Pro-Public, an advocacy organization, in 2060 BS (2003), and the apex court, in its verdict in 2065 BS (2008 AD), has directed the government to immediately take stock of the groundwater resource in the Kathmandu valley and make necessary policy and institutional arrangement for sustainable utilization and management of groundwater resources in the whole country. Page | 2 Main Report In Nepal, no extensive investigation work related to the groundwater was carried except in Terai and Kathmandu valley. In order to carry out the groundwater studies of the country first step is to find out the probable areas where groundwater could be found. Landform and topography of a place determines the recharge and transmission of ground water of a region. The entire process of water movement depends largely on the elevation of the area. Various studies have shown that ground water occurrence is influenced by the climate, physiography, drainage and geology of the area. The delta, transitional and flood plain are reported to have very good ground water potential followed by pediplains and Pediments. The hills and inselbergs have no prospects of ground water. In the hilly area, the first step of groundwater related study is to look for the existence of valleys. As already stated these are the areas where the most of the settlement occurs and where need of water is most. In Nepal no substantial data base is found about the occurrence of valleys. Since the GWRDB is trying to extent its working area beyond Terai, it is trying to find out the information about the existence of valley in the country with fair amount of settlement and having areas more than 200ha. As a part of this the present study entitled “Inventory of valley” is intended to carry so that it could be the base for further investigation work in the mid hill valley of the country. 1.3 Study Area The study area covers the entire mountainous region of Nepal. Nepal is a mountainous country covering more than 80% hilly region. 1.3.1 Topography For a small country, Nepal has great physical diversity, ranging from the Terai Plain–the northern rim of the Gangetic Plain situated at about 60 meters above sea level in the south–to the almost 8,848-meter-high Mount Everest, locally known as Sagarmatha, in the north. From the lowland Terai belt, landforms rise in successive hill and mountain ranges, including the stupendous rampart of the towering Page | 3 Main Report Himalayas, ultimately reaching the Tibetan Plateau beyond the Inner Himalayas. This rise in elevation is disrupted by valleys situated between mountain ranges. Within this maze of mountains, hills, ridges, and low valleys, elevation (altitudinal) changes resulted in ecological variations. 1.3.2 Drainage and River System Nepal's rivers can be broadly divided into three categories in accordance with their origins. The first category comprises the three main river systems of the countrythe Koshi, Gandaki and Karnali river systems, all of them originating from glaciers and snow-fed lakes (Figure 1.1). Figure 1-1: Major Drainage system of Nepal The Koshi river system consists of the Tamor, Arun, Dudhkoshi, Likhu, Tamakoshi, Sunkoshi and Indravati rivers. Of these, the Arun and Sunkoshi originate in Tibet. The confluence of these rivers is at Tribeni (near Dharan) in Sagarmatha Zone. Flowing for almost 10kms through a narrow gorge before entering the plains, the "Sapta Kosi" or he "Koshi" swollen with the waters of the seven rivers; finally merges into the Ganges. Page | 4 Main Report The Gandaki river system in central Nepal consists of the Kaligandaki, Budhigandaki, Marsyanghi, Trishuli, Seti, Madi and Daraundi rivers. The Kaligandaki is the longest river and the Trishuli, the main tributary of this system. The Kaligandaki originates in Mustang and converges with the Trishuli at Deoghat in Chitwan. The river is then called the Narayani and goes on to meet the Ganges. The Karnali river system in western Nepal consists of the Humla Karnali, Mugu Karnali, Seti and Bheri rivers and is the longest river system in the country. The Humla Karnali, which rises in Tibet, is the main tributary. After entering India, this river assumes the name Gogra. Rivers like the Mechi, Mahakali, Bagmati, Kamala, Rapti, etc., most of which have their origin in the Mahabharat range, constitute the rivers of the second category. The Bagmati, which rises at Bagdwar and drains out through the Chobhar gorge, is the principal river of the Katmandu Valley. Streams and rivulets originating mostly from the Chure hills make up the third category; these rivers rely on monsoon rains and are otherwise dry. 1.3.3 Physiography and Geology Nepal is divided into five physiographic regions which are almost parallel to each other, running from west to east. They are: the high Himalayan region, high mountain, middle mountain, Siwaliks and Terai (Figure 1.2) and A summary of the major characteristics is given in Table 1.1. Page | 5 Main Report Figure 1-2: Physiographic Sub-division of Nepal Table 1-1: Summary of Characteristics of physiographic sub-division of Nepal Physiographic region Area (hectares) Percentage High Himalayan Region 3 447 500 23.7 High Hills Region 2 889 500 19.7 Middle Hills Region 4 350 300 29.5 Siwalik 1 888 600 12.7 Terai 2 142 200 14.4 Total 14 718 100 100 Source :- MOAC (2004) Page | 6 Main Report High Himalayan region: This region which is always covered by snow occupies 23.7% of the total land – 3 447 500 ha. Its altitude ranges from 3 000 m to 8 848 m. The mountains are very steep with active glacier systems. The geology consists of gneiss, schist, limestone and shale of different ages. Physical weathering predominates and soils are very stony. This region falls largely within the alpine and arctic climate regimes, so there are active glacier systems where there is enough precipitation in high catchments. The climate is dependent on elevation and location in the mountain massifs. The few pockets of arable land of Solukhumbu, Mustang, Manang and Dolpa are the result of a unique combination of aspect, shelter from wind and availability of water for irrigation. Characteristic landforms are glaciers, cirque basins, moraines, U-shaped valleys and avalanche slopes. Bedrock in most of the areas is exposed at or near the surface including gneisses, schist and the Tethys sediments. Less than 1% of the region has soil and climate suited to crop production and then only where irrigation is available. High Hills (or Mountain) region: The altitude of this region ranges from 2 000 m to 2 500 m and it lies below the permanent snow line. This region occupies 2,899,500 ha making up 19.7% of the country. It has a cool climate and receives heavy to moderate snow in winter. Mountain slopes are very steep but there are some flat valleys as well. The geology is characterized by phyllite, schists, gneiss and quartzite of different ages. Soil formation on the slopes is slow and they are rocky. This region borders the Middle Hills to the south and the high Himal to the north. The boundaries are defined by changes in geomorphic processes, bedrock geology, climate and relative relief. This region has more metamorphosed and structurally consolidated rocks. Gneisses and garnetiferous mica schists are common. Most of the major valleys have been glaciated. High river gradients and enhanced river down-cutting resulted in the formation of deep canyons since glaciations. Agriculturally this region is of lesser importance. After the snow melts the mountains are covered with thick grasses and livestock like sheep, yak, and other mountain animals graze in this region. In the valleys, in summer, one crop a year Page | 7 Main Report can be harvested. The crops are potato, naked barley, buckwheat, and maize. Food grown here is not enough to support the population and more has to brought in. Middle Hills (or Mountain) region. This region includes a wide range of physiography. Its area is 4 350 300 ha. - about 29.5% of the area of the country. Mountain peaks range up to 2 000 m with narrow river valleys. The mountains are the Mahabharat range. The geology consists of a complex of phyllite, schists, quartzite of Cambrian to Precambrian ages and granites and limestones of different ages. The climate ranges from warm subtropical to warm temperate. The higher peaks receive occasional snow whereas some lower parts receive occasional frost in winter, which causes damage to crops. Soils are extremely variable because of the differences in bedrock, geomorphology and microclimate. The southern margin mostly consists of a prominent belt of uplifted mountains known as Mahabharat Lekh. This belt is made up of deeply weathered granite, limestone, dolomite, shale, sandstone, slate and quartzite; is intensively cultivated and is home for more than 60% of the population. It produces most of its food, yet food is always transported from surplus regions to this area. Subtropical dense forest occupies the nonagricultural land. Siwalik region: This region lies at the foot of the Mahabharat range. Its area is 1 888 600 ha: 12.7% of the total land. Altitudes range from 300 m to 1 800 m. The geology mainly consists of tertiary mudstone, sandstone, siltstones and conglomerate. Soils vary depending on the materials from which they are developed. There are several inner valleys or duns, which are densely populated. Because of alluvial deposition these valleys are very fertile. The landscape is very rugged and unstable, consisting of weakly consolidated Tertiary sediments with gentle to strongly sloping dip slope. Siwalik soils are unable to retain high precipitation which frequently occurs resulting in flash floods. Duns, a very important part of the Siwalik landscape, are structurally stable and sometimes, in the past, their outlets were blocked by rapid tectonic uplift of the Siwalik range. The major dun valleys are: Chitwan, Dang, Deokhuri, Surkhet, Trijuga and Kamala. Climate in the duns is modified by the regular occurrence of winter fogs; otherwise it is very dry. Page | 8 Main Report The Terai region: The Terai, a flat extension of the southern Indo-Gangetic plain, occupies 2 142 200 ha, 14.4% of the country. Altitudes range from 66 m to 300 m. The region enjoys a warm sub-tropical climate and its alluvial soils are fertile. It is the granary of Nepal. Wherever irrigation is available the land is intensively cultivated. It consists of recent and post-Pleistocene alluvial deposits forming a piedmont plain adjacent to the Himalayan ranges. Although the whole length of the Terai has a common geomorphology, it has obvious differences in land use due to presence of different land systems and land units. The obvious difference is the increased amount of rice cultivation in the eastern Terai indicating a greater proportion of higher quality alluvial soils and more availability of water/rainfall compared to the west. 1.3.4 Climate There is a wide diversity in landscape, altitude, topography and temperature in the country. Temperatures range from arctic to tropical. The High Himalayan region is always below freezing whereas the Terai and the low valleys are always warm. In winter mornings and nights in the hills are bitterly cold and days are chill whereas in the plains and the river valleys mornings and nights are chill and the days are pleasant. Summers in the hills are pleasant but in the plains and valleys are swelteringly hot. January is the coldest and June and July the hottest months. Rainfall and temperature are the two main factors affecting Nepalese agriculture. Rainfall: 80% of precipitation falls during June to October. The monsoon enters Nepal from the east which receives the first rain; the west gets rain about a week later. The western part receives comparatively less rain than central and eastern parts. The average rainfall in the country is a little above 1 000 mm. Most of the eastern and central hilly areas receive 1 500 – 2 500 mm; the west gets 1 000 – 1 500 mm. Seasonal distribution of precipitation varies from east to west. The seasonal distribution of precipitation is shown in Table 1.2. Page | 9 Main Report Table 1-2: Seasonal rainfall distribution Region Pre-monsoon Monsoon Post-monsoon Winter Terai 4-11% 80-98% 2-7% 2-5% Hill 2-20% 79-92% 1-11% 2-9% Mountain 8-24% 72-80% 1-9% 4-17% Winter precipitation is due to the south west monsoon which passes over the driest area of India so the water vapour almost dries out by the time it reaches Nepal. This rain is low in volume but very important for winter crops. Rainfall data from meteorological stations show that the country receives as high as 5 100 mm and as low as 250 mm rain per annum. Rainfall variation is very high, the lowest precipitation is in small rain-shadow areas, for example in the Mustang district of the Himalaya Region, and falls as snow. From March to May there is little or no precipitation and evapotranspiration is maximal. Atmospheric temperatures as well as water requirement of crops are high. From mid-May to mid-October precipitation is sufficient to meet the water requirement of all crops except rice. Temperature: Temperature is directly related to altitude. For a rise of 100 m, the mean annual temperature drops by 0.5°C. Latitude also affects the temperature. For every 3° north, the mean temperature would fall by 1°C. Temperature falls slowly during the monsoon because of heavy clouds and rain and continues to drop as winter starts. January is the coldest month and June-July are the hottest months. Temperatures tend to rise from east to west. The highest temperature recorded is 46°C (114.8° F) at Chisapani in Bardiya district and the lowest -26° C at Thakmarpha in Mustang district. 1.4 Objective and Scope of Works The overall objective of works includes the finding of all intermountain valleys in the country. This will create the data bank for future groundwater investigation work in Page | 10 Main Report hilly areas. The first phase of the study involves the finding of valley in the mid hill region that have the area of more than 200ha. Particularly the scope includes 1. Prepare contour map from data available at the Department of Survey. 2. Pre-processing and spatial analysis of the contour map for valley delineation 3. Prepare GIS based map of the valley 4. Prepare reports including all above mentioned things 1.5 Structure of the Report This report is the outcome of rigorous study on literature review, data and map collection, data processing using GIS for preparation of DEM, Slope Map and Hillshade map, use of Modelbuilder in ArcGIS for model running and extraction of map for valley inventory. The summary of literature review, methodology, results and output maps are presented in the comprehensive report. The structure of the final report is as follows: 1 Introduction 2 Methodology 3 Valley: Definition and Terminology 4 Valley Inventory of Nepal 5 Results and Recommendations The final report also consists of list of reference and Annexes. 1.6 Limitation of the Study As far as we understand, this is the first of this kind of study in Nepal that is especially focused to delineation of valley of Nepal and prepare their inventory. Topographical maps used for this study were published in 1996 by Nepal Government topographical survey department, Min Bhawan, Kathmandu Nepal in co-operation with the government of Finland. These maps were compiled from Page | 11 Main Report 1:50,000 scale aerial photographs taken in 1992 and they are available in two different scale and size. For Terai and Middle Himalayan region 7.5 minute quadrangle maps are available in 1:25,000 scale and for higher Himalayan range 15 minute quadrangle maps are available in 1:50,000 scale. Page | 12 Main Report 2. Approach and Methodology 2.1 General Approach The broad objective of the study is to prepare Inventory of Valleys of Nepal with area larger than 200 ha as mentioned in ToR. In this connection, the consultant has proposed the best professionals with well co-coordinated and multidisciplinary team who has been working to execute the project in a team effort including technical, managerial, financial, social and other related fields. The consultant's general approach to execute the project is listed below and briefly described: • Adopt a good Planning and management practice to incorporate the project. Employ the state of the art knowledge available and complete the study with high level of professional output. • Arrange the project management structure and assign the specific responsibilities to all the professional and other staffs in line with the objective of the present study. • Facilitate an in-house discussion with all the professionals and other staffs engaged in the project to find out the best way to carry over different project activities and sort out the probable problems and solutions to generate efficient result. • General monitoring on the periodic basis to check the progress on quality and quantity aspect of the project implementation and find out the gaps to improve the performance at a later stage. • Good co-ordination with the client throughout the project implementation period. • Readiness to accept challenge to deliver high level of professional service to the client and show competency to create best performance level and quality. Page | 13 Main Report 2.2 Methodology The study methodology was based on the Terms of Reference as well as the proposal submitted to the GWRDB. A short description of the activities carried out is given below. 2.2.1 Literature review and Data Collection Available relevant reports, literatures were collected and reviewed. The maps primarily included the recently published topographic, geological, land use, and other relevant thematic maps of Nepal were collected. In this study the digital layers, viz. contours, transportation, house spot heights, units, etc., drainage, prepared land use Government and of land Nepal, cover, Survey Department; was used. The collected topographic maps were grouped in GIS environment. Topographic map of each districts of Nepal was delineated by using the GIS software. The district boundary was extracted from the district boundary map of Nepal (source: http://geoportal.icimod.org/Home/DataSetDetail?dataSetId=17). 2.2.2 Use of ArcGIS: Model builder GIS is a collective term commonly accepted for describing computer systems that can manipulate geographic data. ArcGIS Spatial Analyst tool was used which provides a broad range of powerful spatial modeling and analysis features. This tool can create, query, map, and analyze cell-based raster data; perform integrated raster/vector analysis; derive new information from existing data; query information across multiple data layers; and fully integrate cell-based raster data with traditional vector data sources. In spatial analysis, Model Builder tool was used in ArcGIS. This tool builds models by building and connecting processes. A process is simply a tool plus its variables. Digital Elevation Model (DEM) of each districts of Nepal have been prepared based on the grouped and district delineated digital topo-map. DEM is used to prepare slope for valley delineation. The DEM was prepared by using contour, district boundary and drainage layer of each district. In the model builder, contours with contour value 20 and or 50 m Page | 14 Main Report intervals, district boundary as boundary and drainage as stream were added as input parameter and output DEM with cell size of 20. From the DEM, slope map of the district was prepared which were reclassified in to two classes with the threshold value of 10 degrees. From the reclassified slope map, the conditional tool in the model builder was used to extract the areas less than 10 degrees and converted to polygon. Finally, to this polygon layer selection tool was used to extract the valleys with area larger than 200 ha. The extracted valley layer is plotted into the Google Earth Map for validation. The model builder window is shown in figure 2.1 and details of the methodology are described hereunder and the general work flow chart is shown in figure 2.2. Figure 2-1: View ArcGIS 9.3 Model Builder Window Page | 15 Main Report Figure 2-2: Work Flow Chart for Valley Delineation 2.3 Report Preparation The result of valley inventory by using GIS was presented in the form of report. The final report consists of results of literature review, brief details of delineated valleys and maps. Page | 16 Main Report 3. Valley: Definition and Terminology 3.1 Definition of Valley Valleys are among the most prominent topographic features in the earth surface. A valley is described as (R. Straumann, 2010; Bates, R.L., Jackson, J.A. 1990): • a low area more or less enclosed by hills; • a long, narrow depression in the Earth’s surface, usually with a fairly regular; and • any low-lying land bordered by higher ground; especially an elongate, relatively large, gently sloping depression of the Earth’s surface, commonly situated between two mountains or between ranges of hills or mountains, and often containing a stream with an outlet. It is usually developed by stream erosion, but may be formed by faulting. a broad area of generally flat land extending inland for a considerable distance, drained or watered by a large river and its tributaries; a river basin. Example: the Mississippi Valley. According to the above definitions, characteristics of valleys include the following: • Valleys are low areas or depressions relative to their surroundings. • Valleys are elongated. • Valleys are (gently) sloping. • Valleys often contain a stream or a river. The terms ‘valley floor’ or ‘valley bottom’ is a relatively broad, flat region within a valley and will thus inherit the characteristics of valleys listed above. Page | 17 Main Report 3.2 Types of Valley 3.2.1 V and U Shaped Valley A valley formed by flowing water, or river valley, is usually V-shaped. The exact shape will depend on the characteristics of the stream flowing through it. Rivers with steep gradients, as in mountain ranges, produce steep walls and a bottom. Shallower slopes may produce broader and gentler valleys. However, in the lowest stretch of a river, where it approaches its base level, it begins to deposit sediment and the valley bottom becomes a floodplain. This valley floor “is produced by lateral erosion, accumulation or a combination of the two”. The terms U Shaped Valley, glacial trough or glacial valley is the valley that has been over deepened by glacial erosion. In more specific, U-shaped valley has a wide valley floor with steep sides formed by glacial erosion and the shape of a glacial trough more resembles a parabola than the letter "U”. 3.2.2 Hanging Valley Hanging valleys are often (probably nearly always) glacial features. Hanging valley area the tributary valleys whose floor is at a higher level than the main valley, caused by the latter’s deepening by glacial erosion. They are smaller, shallower troughs are cut by smaller tributary glaciers. 3.2.3 Rift Valley A rift is defined as a valley with steep sides; formed by a rift in the earth’s crust. Whittow (2000) defines a rift valley as “a linear depression or trough created by the sinking of the intermediate crustal rocks between two or more parallel strike-slip faults. The structure is known as a graben and the accompanying morphological feature as a rift valley. The magnitude of rift valley varies from those of the midoceanic ridges, and the Red Sea graben, to the East African Rift and the Rhine graben. Page | 18 Main Report 3.2.4 Open River Valley (Dale) A valley formed by flowing water, or river valley, is usually V-shaped. The exact shape will depend on the characteristics of the stream flowing through it. Rivers with steep gradients, as in mountain ranges, produce steep walls and a bottom. Shallower slopes may produce broader and gentler valleys. However, in the lowest stretch of a river, where it approaches its base level, it begins to deposit sediment and the valley bottom becomes a floodplain. The marginal figure shows the typical river valley. 3.2.5 Tectonic Valley (Intermountain Basin) The landforms characterized by relatively steep, mountainous sides and flat floors. The steep sides are created by displacement on faults such that the valley floor moves down relative to the surrounding margins, or, conversely, the margins move up relative to the floor. Differences in the elevations of valley floors and surrounding mountains or plateaus range from only several hundred metres to. The widths of tectonic valleys and basins vary from as little as 10 kilometres to more than 100 kilometres. Their lengths typically are hundreds of kilometres, but range from a few tens to thousands of kilometres. The vast majority of tectonic basins and valleys is produced by an extension of the Earth’s crustand the subsequent dropping of a block of crust into the space created by the divergence of large crustal blocks or lithospheric plates. The extension of the brittle crust causes it to fracture, and as the adjoining crustal blocks or plates move apart, a smaller block slides down into the resulting gap. Page | 19 Main Report 4. Valley Inventory of Nepal This section of the report summaries the outcomes of intensive inventory study of valleys in Nepal. The outcome of this report can be takes as the baseline information for land resource mapping, detail study of valleys in water resource study or groundwater resources of the valley. It also helps to find out the area to focus for further study, planning and development. 4.1 General Consideration This section summarizes the result of GIS based valley inventory of Nepal. The inventory of valley in Nepal was done on the following basis: • Valleys are the elongate depression of the Earth’s surface. Valleys are most commonly drained by rivers and may occur in a relatively flat plain or between ranges of hills or mountains. • Most common type of valleys present in the Nepal Himalayas are River Valleys, Glacier Valleys, Intermountain Valleys and Dun Valleys. • As per the TOR, the valleys with area greater than 200 ha (2 sq. km) are considered for the valley delineation. • There is no universally fixed threshold for slope of valley, but in some scientific works, 3-4 degrees have been reported. Considering the huge topographic variation, the undulation within the single valleys and aerial extent of the valley, here, in this study, the threshold of slope for valley delineation was taken as 10 degrees. As the results of the works are validated with the Google Earth Map, they are quite good and can be judged visually. • The characteristics of valley include gross area, average elevation, name of valley, Name of VDCs that includes the Valley and Major landuse Pattern. Page | 20 Main Report 4.2 Valley Inventory: Results The main approach for this study includes application of GIS for valley delineation. The inventory and delineation valleys are the basic information to carry out the further groundwater availability study in the hill and mountain region of Nepal. The result of the study shows that there are 102 major valleys with area larger than 200 ha; are present in Nepal excluding Glacier valleys in higher Himalayan region and Dun valleys like Dang-Deukhuri and Chitwan Valley. The major valleys are shown in figure 4.1. The zone wise results of inventory of the Valleys are shown in hereunder: Page | 21 Main Report Figure 4-1: Map showing valleys of Nepal Page | 22 Main Report 4.2.1 Mechi Zone This is the eastern-most district of Nepal. it consists of 3 hilly districts and 1 Tarai district. Among these districts, there are three valleys in Ilam district. The details of the valleys in Ilam district are shown in table 4.1. Table 4-1: Valleys of Mechi Zone, Nepal Mechi Zone District Name Name of Valley Name of Area of the Average Major Remarks VDCs/NPs Valley (ha) Elevation, Landuse m Taplejung - (Only Glacier - - - - - - - - Valley) Panchthar - Ilam - Agr. Land, Bare Area, Mahamai- Mahamai and Dhanbari Dhanbari 160-200 2652 Forest, m River, Builtup area Agr. Land, Bare Area, 200-250 Toribari Sakfara Forest, 244 m River, Builtup area Agr. Land, Bare Area, 140-180 Chulachuli Chuchali 3086 Forest, m River, Builtup area Page | 23 Main Report 4.2.2 Koshi Zone This zone consists of 6 districts; out of which there are 4 hilly districts and 2 Tarai district. Among these districts, only one valley exists in Samkhuwasava district. The details are shown in table 4.2. Table 4-2: Valleys of Koshi Zone, Nepal Kosi Zone District Name Name of Valley Name of Area of Average Major Remarks VDCs/NPs the Valley Elevation, Landuse (ha) m Bhojpur - - - - - - Dhankuta - - - - - - Samkhuwasava Tumlingtar Khandbari NP 682.54 400 Agriculture, Builtup area, Forest Terhathum - - - - - - 4.2.3 Sagarmatha Zone This zone consists of 6 districts; out of which there are 4 hilly districts and 2 Tarai district. There are two valleys in Udayapur district. The details are shown in table 4.3. Table 4-3: Valleys of Sagarmatha Zone, Nepal Sagarmatha Zone District Name Name of Valley a. Trijuga Udayapur Page | 24 Name of Area of Average VDCs/NPs the Valley Elevation, Landuse (ha) m 19760 ha 130 Trijuga NP, Major Remarks Forest, Jogidaha, Agriculture, Hadiya, Grass/shrub Main Report Sundarpur, land, River Beltar b. Katari Katari, Tribeni 6360 ha 220 and Risku Forest, Agriculture, Grass/shrub land, River Khotang - - - - - Okhaldhunga - - - - - Solukhumbu - - - - - 4.2.4 Janakpur Zone This zone consists of 6 districts; out of which there are 3 hilly districts and 3 Tarai district. There are six valleys in Sindhuli and Ramechhap district. The details are shown in table 4.4. Table 4-4: Valleys of Janakpur Zone, Nepal Janakpur Zone District Name Name of Valley Name of Area Average Major VDCs/NPs of the Elevation, Landuse Valley m Remarks (ha) a. Bhimsensthan Bhimsensthan 857 400-440 , Belghari Forest, Agriculture, Grass/shrub land, River Sindhuli b. Dhura BazarDhundrebas Kamalamai NP 1283 530-550 Forest, Agriculture, Grass/shrub land, River Page | 25 Main Report c. Ranibas-Dudhauli Kamalamai 12799 190-320 Forest, NP, Ranibas, Agriculture, Hatpate, Grass/shrub Pipane, land, River Harsahi, Sirthauli, Tadi, Dudhauli, Ladabhir d. Kalyaneshwor Kalyaneshwor 1160 180-230 F Forest, Agriculture, Grass/shrub land, River e. Kapilakot Pipalmadi, 7079 170- 300 Forest, Mahendrajaya Agriculture, di, Grass/shrub Kalpabrishya, land, River Mahadevstha n, Dadigurase Ramechhap Manthali Manthali, 599 480-500 Agriculture, Bhatauli, Builtup, Maluwajor Forest, and Pakarbas Bareland and River Dolakha - - - - - - 4.2.5 Bagmati Zone This zone consists of all 8 hilly districts. There are 9 valleys in this zone excluding Kathmandu valley. The details are shown in table 4.5. Page | 26 Main Report Table 4-5: Valleys of Bagmati Zone, Nepal Bagmati Zone District Name Name of Valley Name of Area Average Major VDCs/NPs of the Elevation, Landuse Valley m Remarks (ha) Sindhupalchowk - - - - - - Rasuwa - - - - - - Agr. Land, Ratmate, a. Tadi Valley 500-640 River, m Forest, 1985 Budhasing Grassland Agr. Land, Bidur NP, b. BidurKhadgabghan Nawakot 460-650 River, m Forest, 1635 Trishuli Valley gyang Grassland Kholegau, Agr. Land, Chaugada, c. Ratmate Valley Thansingh, 440-460 River, m Forest, 509 Thalebas, Grassland Ganesthan Dhading Salyantar 717 580-640 m Agr. Land, River, a. Salyantar Forest, Grassland Jyamrung, b. Ankhu Khola Valley Tripureshwor, Ainchok Page | 27 362 460-500 m Agr. Land, River, Forest, Main Report Grassland Nilkantha, 280 Sunaulabazar, c. Dhading Besi 550-600 Agr. Land, m River, Muraribhanjy Forest, ang Grassland Kavrepalanchowk Agr. Land, Mathurapathi, Mathurapathi 1120- River, 1160 m Forest, 359 Methinkot, Grassland Khanalthok Panchkhal, Agr. Land, Hokse, Panchkhal Deuvhumi 800-880 River, m Forest, 1907 Baluwa, Grassland Kharelthok Banepa, Agr. Land, Panauti, 1440- River, 1460 m Forest, 2460 Banepa-Panauti Dhulikhel, Ugratara, Nala Grassland 4.2.6 Narayani Zone This zone consists of 5 districts; out of which, four district including Chitwan are Tarai and Dun valley and one hilly district. There are 9 valleys Makawanpur district. The details are shown in table 4.6. Table 4-6: Valleys of Narayani Zone, Nepal Narayani Zone District Name Page | 28 Name of Valley Name of Area Average Major VDCs/NPs of the Elevation, Landuse Remarks Main Report Valley m (ha) Makawanpur Agr. Land, Palung and Palung 1740- River, 1860 m Forest, 424 Daman Grassland Agr. Land, Sreepur Shreepur Chhatiwan 280-320 River, m Forest, 483 Chhatiwan Grassland Agr. Land, Sreepur Shreepur Chhatiwan 240-340 River, m Forest, 1756 Chhatiwan Grassland Agr. Land, SarikhetPhalas 340-360 River, m Forest, 322 Phalase e,Raksirang Grassland Agr. Land, Makawanpurg Makawanpurgadi adi, 480-580 River, m Forest, 542 Ambhanjyang Grassland Agr. Land, Faparbari Faparbari 240-300 River, m Forest, 1765 Grassland 170-200 Raigau Raigau 1694 m Agr. Land, River, Forest, Page | 29 Main Report Grassland Hadikhola, Agr. Land, Padampokhari 360-470 River, m Forest, 12980 Hetauda , Churiyamai, Hetauda NP, Grassland Agr. Land, Parsa Wildlife Parsa Wildlife Reserve, 140-320 River, m Forest, 10500 Reserve Manahari Grassland 4.2.7 Gandali Zone This zone consists of 5 districts hilly and high Himalayan districts including Manang. There are 25 valleys in this zone including Pokhara-Lekhnath valley. The details are shown in table 4.7. Table 4-7: Valleys of Gandaki Zone, Nepal Gandaki Zone District Name Name of Valley Name of Area Average Major VDCs/NPs of the Elevation, Landuse Valley m Remarks (ha) Gorkha Agr. Land, Prthivinarayan Daraudi River Valley NP, Mirkot, 360-400 River, m Forest, 838 Khoplang Grassland Agr. Land, Dhuwakot, 380-460 River, m Forest, 237 Birti-Seraphat Mirkot Grassland Page | 30 Main Report Agr. Land, Chyangli a Chyangli 460-540 River, m Forest, 528 Grassland Agr. Land, Chyandli, 1499 360-480 River, m Forest, Chyangli Dhuwakot Grassland Agr. Land, Palungtar Palungtar 540-580 River, m Forest, 633 Grassland Lumjung Agr. Land, Bhorletar, Bhotewadar Isaeshwor, 440-500 River, m Forest, 466 Bangre Grassland Agr. Land, Ramgha, Ramgha Suryapal, 400-440 River, m Forest, 533 Taksar Grassland Agr. Land, Parewadada, Sundarbazar Sundarbazar, 540-660 River, m Forest, 714 Bhoteodar Grassland Agr. Land, Dhamilikuwa, Chepe Valley 480-620 River, m Forest, 1058 Chakratirtha Grassland Tanahu Page | 31 Devghat Devghat 912 210-240 Agr. Land, Main Report m River, Forest, Grassland Agr. Land, Simaltar Bandipur 660-720 River, m Forest, 256 Grassland Agr. Land, Anbukhairani, 300-400 River, m Forest, 720 Satrasaye Phat Bandipur Grassland Agr. Land, Bhanu, Cudi-Tuhurepasal Barbhanjyang, 480-500 River, m Forest, 616 Basantapur Grassland Agr. Land, Baisjagare Purkot 460-540 River, m Forest, 414 Grassland Agr. Land, Farakchaur Byas NP 440-460 River, m Forest, 352 Grassland Agr. Land, Jamunebhanjy Jamune_Adhikarithok ang, Chhang, 500-540 River, m Forest, 629 Manpang Grassland Damauli Byas NP, Kyamin, Page | 32 300-400 1430 m Agr. Land, River, Main Report Syamgha Forest, Grassland Khairanitar, Khairanitar- Agr. Land, Dulegauda, 440-560 River, m Forest, 1902 Dulegauda Dhoefirdi, Firfire Grassland Resing, Agr. Land, Majhkot, Bhimad-Risingpatan 400-460 River, m Forest, 687 Bhimad, Chhang Grassland Kaski Agr. Land, River, Pokhara NP, Forest, Lekhnath-Pokhara- Lekhnath NP, Hemja Bharatpokhari 630-1080 12050 Grassland, m Lake, , Hemja Buildup Area Agr. Land, River, Forest, Lhahachok, 1100Lhachok-Ghachok Ghachok, 1417 Grassland, 1340 m Sardikhola Lake, Buildup Area Syanja Agr. Land, Kuwakot, Jyagdi Chapakot, 340-440 River, m Forest, 1409 Ratnapur Grassland, Sakhar Sakhar 226 Agr. Land, 320-400 River, Page | 33 Main Report m Forest, Grassland, Agr. Land, Waling NP, Waling (Adhikhola River, Chhangchhan 700-740 Forest, 937 Valley) gdi, Sworek, m Darsing Grassland, Buildup Area Agr. Land, River, 780-840 Putalibazar-Thulibesi Putalibazar NP Forest, 623 m Grassland, Buildup Area Manang - (Glacier Valley Only) - - - - - 4.2.8 Dhaulagiri Zone This zone consists of 4 hilly and high Himalayan districts including Mustang. There are 2 valleys in Baglung and Parbat district. The details are shown in table 4.8. Table 4-8: Valleys of Dhaulagiri Zone, Nepal Dhaulagiri Zone District Name Name of Valley Name of Area Average Major VDCs/NPs of the Elevation, Landuse Valley m Remarks (ha) Baglung Agr. Land, Dhorpatan Arjewa 2840- River, 2940 m Forest, 837 Grassland, Page | 34 Main Report Shrubland Myagdi - (Only Glacier Valley) Parbat - - - - Devisthan - Agr. Land, 780-900 Devisthan-Falebas Falebas, 464 Forest, m Mudikuwa Shrubland Mustang 4.2.9 Lumbini Zone This zone consists of 6 districts. Among them, there are 3 hilly and 3 Tarai districts. There are 13 valleys in this zone. The details are shown in table 4.9. Table 4-9: Valleys of Lumbini Zone, Nepal Lumbini Zone District Name Name of Valley Name of Area Average Major VDCs/NPs of the Elevation, Landuse Valley m Remarks (ha) Argakhanchi Agr. Land, River, 300-320 Rapti Bhalubang Juluke Forest, 414 m Grassland, Shrubland, BarrenLand Agr. Land, Ransin Khola Siddhara 340-400 River, m Forest, 201 Grassland, Page | 35 Main Report Shrubland, BarrenLand Agr. Land, River, 460-520 Siddhara Siddhara Forest, 365 m Grassland, Shrubland, BarrenLand Palpa Madanpokhar a, Rupse, Agr. Land, Chidipani, River, 700-720 Madiphat Bodhapokhara 1516 Forest, Tinau m thok, Lake, Chirtungdhara Bareland , Kaseni Agr. Land, Gejha Gejha 340-480 River, Kaligand m Forest, aki 562 Bareland Rampur, Agr. Land, Khaliban, Rampur 320-440 River, Kaligand m Forest, aki 2356 Darchha, Gadakot Bareland Agr. Land, Argali Argali 620-680 River, m Forest, 197 Bareland Hungi, Hugi 360-580 390 Haklang m Agr. Land, River, Kaligand aki Forest, Page | 36 Main Report Bareland Agr. Land, River, Parbas Bhainse 840-880 Tansen NP, Forest, 174 Telgha kati m Lake, Bareland Agr. Land, Jdewa Jadewa 130 River, Jhumsa Forest, Khola `` Bareland Gulmi Agricultural Rupakot, Land, 620-650 Turang, 251 Majuwabazar Balithum, Majuwa Forest, m bazar Brassland Juvung and Forest Agricultural Marbung, Land, Wagla, Simaltari Simaltar 960-1020 Forest, 2277 Dhamir, i m Brassland Amarpur and Forest Agricultural Dhurkot, Land, 880-920 Amarpur, 206 Hulake Ismarahasthal, Forest, Hulake m Brassland Dalamchaur and Forest 4.2.10 Rapti Zone This zone consists of 4 hilly districts and 1 Tarai districts totaling 5 districts. There are 10 valleys in this zone. The details are shown in table 4.10. Page | 37 Main Report Table 4-10: Valleys of Rapti Zone, Nepal Rapti Zone District Name Name of Valley Name of Area Average Major VDCs/NPs of the Elevation, Landuse Valley m Remarks (ha) Pyauthan Arg. Land, Bare Area, 340-400 Darban Bangesal Forest, 1036 m Grassland, River, Shrubland Ramdi, Khaira, Arg. Land, Dakhanwadi, Bare Area, Bijuwar, 740-840 Kwadi-Bijawar Pythan Forest, 965 m Grassland, Khalanga, River, Dharmawati, Shrubland Maranthana Arg. Land, Bare Area, Gothiwang, 640-760 Barjiwang, Forest, 1407 Bajipur-Sallibesi Belwaspur, m Grassland, River, Bingri, Sari Shrubland Rukum - - - - - - Rolpa - - - - - - Salyan Kalamiti KalimatiRampur Rampur Page | 38 500-560 432 m Agr. Land, River, Main Report Forest, Grassland, Bare Area, Shrub Land Agr. Land, River, Kalimati 410-440 Rampur and Forest, 599 Babai Valley-1 m Lkalimati Grassland, Bare Area, Kalche Shrub Land Agr. Land, River, 340-380 Vavai Valley-2 Kavrechaur Forest, 391 m Grassland, Bare Area, Shrub Land Agr. Land, River, Kalamiti Rampur 660-700 Forest, 247 Rampur m Grassland, Bare Area, Shrub Land Agr. Land, River, Phalawang, Rikhe Bagar- 830-920 Chhayachhetr Forest, 441 Dhungebagar m Grassland, a, Trinebi Bare Area, Shrub Land Lantibazar-Khalanga Chhayachhetr a, Syanikhal, Page | 39 930-980 428 m Agr. Land, River, Main Report Khalanga, Forest, Dandaguan Grassland, Bare Area, Shrub Land Agr. Land, River, Kalimato Babai Valley-3 390-410 Forest, 266 Alche m Grassland, Bare Area, Shrub Land 4.2.11 Bheri Zone This zone consists of 3 hilly districts and 2 Tarai districts totaling 5 districts. There are 11 valleys in this zone. The details are shown in table 4.11. Table 4-11: Valleys of Bheri Zone, Nepal Bheri Zone Dailekh Agr. Land, Narayan NP, 700-740 Dailekh Belpata and Forest, 194 m Grass land, Kalbhairab River, Jajarkot Agriculture, 680-760 Jagatipur Jagatipur 269 Bare Land m and River Surkhet Arg. Lnd, Birendranagar Bare Lanf, NP, 630-720 Surkhet Valley Uttarganga, 5076 m Latikoili, Jarbuta Forest, Grass Land, Builtup Area, River Page | 40 Main Report and Shrub Land Arg. Lnd, Bare Lanf, Forest, 560-620 Gojibazar Rakam Grass Land, 552 m Builtup Area, River and Shrub Land Arg. Lnd, Bare Lanf, Forest, 220-280 Ghatgaon, Grass Land, 2039 Ghatgaon m Tatopani Builtup Area, River and Shrub Land Arg. Lnd, Bare Lanf, Tatopani, Forest, 240-260 Ghatgaon, Grass Land, 1017 Tatopani m babiyochaur, Bidyapur Builtup Area, River and Shrub Land Tatopani, Arg. Lnd, Taranga, Jamungaon Kunathari, Pokharikanda Page | 41 260-340 2106 m Bare Lanf, Forest, Grass Land, Main Report Builtup Area, River and Shrub Land Arg. Lnd, Bare Lanf, Forest, Grass Land, Chhinchu, Chhinchu 1413 Builtup Ramghat Area, River and Shrub Land Arg. Lnd, Bare Lanf, Forest, Bidyachaur, 560-640 Babiyochaur Babiyochaur, Grass Land, 1864 m Builtup Salkot Area, River and Shrub Land Mahelkuna, Arg. Lnd, Gumi, Bare Lanf, Maintada, Forest, 480-560 Dahachaur, m Ramghat, Guthu Page | 42 Grass Land, 6226 Mahelkuna-Gumi Builtup Dasarathpur, Area, River Kafalkot, and Shrub Lekhparajul Land Guthu, Bijaura 400-520 Arg. Lnd, m Bare Lanf, 1186 Main Report Forest, Grass Land, Builtup Area, River and Shrub Land 4.2.12 Karnali Zone This zone consists of 5 hilly and high mountainous districts. In this zone, there are 5 valleys, entirely lies in Jumla district. The details are shown in table 4.12. Table 4-12: Valleys of Karnali Zone, Nepal Karnali Zone Dolpa - - - - - - Kalikot - - - - - - Jumla Arg.Land, Guthichaur Guthichaur 2800- Forest, 2880m Grassland, 285 Shrubland Arg.Land, Chhumchaur, Chhumchaur 2680- Forest, 449 Patarasi 2800 m Grassland, Shrubland Talium, Arg.Land, Mahatgaun, Jumla Khalanga 2280- Kartikswami, 2400 m Chandannath Dhapa Dhapa, Pandawagufa, Page | 43 Forest, 605 Grassland, Shrubland 2360382 2400 m Arg.Land, Forest, Main Report Birat, Grassland, Kanaksundari Shrubland Arg.Land, Depalgaun, Garjyamgkot 2400- Forest, 383 Garjyangkot 2480 m Grassland, Shrubland Humla -(only Glacier valleys are present) Mugu -(only glacier valleys and Rara Lake are present) 4.2.13 Seti Zone This zone consists of 5 districts; among them, there are 4 hilly and 1 Tarai districts. In this zone, there are 2 valleys, Accham and Bajhang districts. The details are shown in table 4.13. Table 4-13: Valleys of Seti Zone, Nepal Seti Zone Accham Arg.Land, Baijinath, Rodikot, Forest, Sanfebagar Jalapadevi, 602 560-620 Grassland, Mastamandau Shrubland Bajhang Subeda, Luyanta, Arg.Land, Rithapata, Chairpur 1160- Chainpur, 1280 m Hemantabada Bajura Page | 44 - Forest, 409 - Grassland, Shrubland - - - - Main Report Doti - - - - - - 4.2.14 Mahakali Zone This zone consists of 3 hilly districts and one Tarai district totaling 4 districts. In this zone, there are 4 valleys, in Baitadi and Dadeldhura districts. The details are shown in table 4.14. Table 4-14: Valleys of Mahakali Zone, Nepal Mahakali Zone Dadeldhura Arg.Land, 300-440 SurnayaJigbuda and Sirsha Forest, 3077 m Mahakali Valley Grassland, Bare Area Arg.Land, 540-680 Budar Alital Forest, 497 m Grassland, Bare Area 1540Amargadhi Amargadhi NP Arg.Land, 218 1580 m Baitadi Arg.Land, 1140Patan Patan Forest, 242 1280 m Grassland, Bare Area Darchula Page | 45 - - - - - - Main Report 5. Results and Discussion The main objective of works includes the finding of all intermountain valleys in the country. This will create the data bank for future groundwater investigation work in hilly areas. The first phase of the study involves the finding of valley in the mid hill region that have the area of more than 200ha. The methodology adopted for the study is data collection and use of GIS. The DEM was prepared by using contour, district boundary and drainage layer of each district. In the model builder, contours with contour value 20 and or 50 m intervals, district boundary as boundary and drainage as stream were added as input parameter and output DEM with cell size of 20. From the DEM, slope map of the district was prepared which were reclassified in to two classes with the threshold value of 10 degrees. From the reclassified slope map, the conditional tool in the model builder was used to extract the areas less than 10 degrees and converted to polygon. Finally, to this polygon layer selection tool was used to extract the valleys with area larger than 200 ha. The inventory and delineation valleys are the basic information to carry out the further groundwater availability study in the hill and mountain region of Nepal. The result of the study shows that there are 102 major valleys with area larger than 200 ha; are present in Nepal excluding Glacier valleys in higher Himalayan region and Dun valleys like Dang-Deukhuri and Chitwan Valley. The results of the study are shown in table 5.1. Table 5-1: Results of Valley Inventory in Nepal No. of Total No. No. of Districts No. of Tarai without Valley Districts Districts of District with Valley Total Number Total area of all of Valleys Valleys of the (200ha) District (ha) 4 1 2 1 3 5982 6 1 3 2 1 682 Page | 46 Main Report 6 1 3 2 2 26120 6 2 1 3 6 23777 8 6 2 - 9 10214 5 1 0 4 9 30466 6 5 1 - 25 31086 4 2 2 - 2 1301 6 3 - 3 13 9039 5 2 2 1 10 6212 5 3 - 2 11 21942 5 1 4 - 5 2104 5 2 2 1 2 1011 4 2 1 1 4 4034 Page | 47 Main Report LIST OF REFERENCES • Sharma, C.K., 1977, Geology of Nepal. Educational Enterprises, Kathmandu, 164 p. • ICIMOD: http://geoportal.icimod.org/Home/DataSetDetail?dataSetId=17 • Straumann, R.K., 2010, Extraction and characterization of Landforms from Digital Elevation Models: Fiat Parsing the Elevation Field • Bates RL and Jackson JA (eds., 1990): “Valley”, “Valley floor”. Glossary of Geology. American Geological Institute, Alexandria, USA. • Gansser, A., 1964: Geology of the Himalayas. John Willy and Sons, London, 289 p. • Environmental Statistics of Nepal, 2011, Published by, Central Bureau of Statistics, Nepal • Climate Record of Nepal, 1994-2011, Department of Hydrology and Meterology, Kathmandu, Nepal • Precipitation Record of Nepal, 1994-2011, Department of Hydrology and Meterology, Kathmandu, Nepal • http://gis4geomorphology.com/hammond-landforms/ • Morgan et al., (2005) Developing Landform Maps Using ESRI’s ModelBuilder, ESRI User Conf. Proc, 11 pgs. • Miller, B.A. 2013. Incorporating tacit knowledge of soil-landscape relationships for digital soil and landscape mapping applications. Dissertation, Department of Geography, Michigan State University, USA. • Brabyn, Lars(2009)'Classifying Landscape Character', Landscape Research,34:3,299 — 321 • http://www.ngiip.gov.np/THEMATIC_MAPS/Physiography.html • http://www.gwrdb.gov.np/pdf_files/gwrdb-gathan.pdf • http://www.ngiip.gov.np/THEMATIC_MAPS/Rivers.html • http://tank-ojha.com/index_files/Page313.htm • ESRI: ArcGIS Spatial Analyst Tutorial Page | 48 Main Report • www.fao.org/ag/AGP/AGPC/doc/counprof/Nepal/nepal.htm • www.ranjan.net.np/ranjan/index.php/resources/geology-of-nepal • MOAC. 2004. Statistical Information on Nepalese Agriculture. Ministry of Agriculture and Cooperatives. Agribusiness Promotion and Statistics Division, Singh Durbar, Kathmandu, Nepal. Page | 49 Main Report Ministry of Irrigation Groundwater Resources Development Board Babarmahal, Kathmandu Inventory of Valley in Nepal [Type the document subtitle] Annex Team involved for the Study: dell Surendra Raj Shrestha, Senior Divisional Hydrogeologist (Corresponding Email: shree_surendraraj@yahoo.com) Surendra Shah, Hydrogeologist (Corresponding email: surendra_shah@hotmail.com) Annex: District Wise Valley Inventory Map of Nepal Results of Valley Inventory in Nepal Total No. of No. of Districts with No. of Districts without Total Number of Valleys Total area of all Valleys of the (200ha) District (ha) No. of Tarai Districts District Valley Valley 4 1 2 1 3 5982 6 1 3 2 1 682 6 1 3 2 2 26120 6 2 1 3 6 23777 8 6 2 - 9 10214 5 1 0 4 9 30466 6 5 1 - 25 31086 4 2 2 - 2 1301 6 3 - 3 13 9039 5 2 2 1 10 6212 5 3 - 2 11 21942 5 1 4 - 5 2104 5 2 2 1 2 1011 4 2 1 1 4 4034 Ilam Samkhuwasava Udayapur Sindhuli Ramechhap Nuwakot Dhading Kavrepalanchowk Makawanpur Gorkha Lamjung Tanahu Kaski Syanja Baglung Parbat Argakhanchi Palpa Gulmi Pyauthan Rukum Dailekh Jajarkot Surkhet Jumla Accham Bajhang Dadeldhura Baitadi District