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Available Online at http://www.journalajst.com ASIAN JOURNAL OF SCIENCE AND TECHNOLOGY Asian Journal of Science and Technology ISSN: 0976-3376 Vol. 09, Issue, 02, pp.7625 -7629, February, 2018 RESEARCH ARTICLE FLOW DYNAMICS OF RIVER DIKHU, NAGALAND *1Lanuyanger Longchar, 2Sharif U. Ahmed and 3Shyama Prasad Biswas 1,2Department of Zoology, Nagaland University, Lumami- 798627, India 3Department of Life Sciences, Dibrugarh University, Assam- 786004, India ARTICLE INFO ABSTRACT Article History: This paper describes the basic concepts of open channel flow and important conditions effecting the Received 18th November, 2017 flow behavior of river channels. The study of open channels traditionally includes the discussion of Received in revised form flow in river. In this paper, the Dikhu river in Nagaland was selected to assess the flow regime in 20th December, 2017 different months/seasons of the year. The statistical interpretation was the most important feature of Accepted 14th January, 2018 prediction during the research tenure. Published online 28th February, 2018 Key words: Describes Channel flow Statistical interpretation. Copyright © 2018, Lanuyanger Longchar et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. INTRODUCTION River ecosystem contains many other smaller types of ecosystems, including many of that which does not lie within Water being a prime natural resource, has many the open-water channel. River ecosystem is also unique in surprising properties that are important to life and it covers that they are relatively small volume, but open, three fourth of Earth’s surface. Quality water is vital to the ecosystems with high rates of energy throughout. social, health and economic well being of all people. Water too Therefore, understanding a river ecosystem is clearly a is a commodity with its inherent nature of falling down challenging and complicated task. Dikhu River is one of the because of the gravitational pull, which creates the storage, the most prominent rivers of Nagaland. River Dikhu, which has a streams, the tributaries and the rivers, that meet in the sea. total length of about 160 km, originates from Nuroto Hill area Rivers are of immense importance geologically, biologically, in Zunheboto district. The river flows across the Mokokchung historically and culturally. Although they contain only and the Longleng districts. The main tributaries of river Dikhu about 0.0001% of the total amount of water in the world at are .Yangyu of Tuensang district and Nanung in the any given time, rivers are vital carriers of water and Langpangkong range in Mokokchung district. The Dikhu nutrients to all areas around the earth. They are critical River is one of the tributaries of Brahmaputra, one of the components of the hydrological cycle, acting as drainage mightiest rivers of India. The Dikhu River is not only a prime channels for surface water. The world’s rivers drain nearly tourist attraction, but also a significant source of livelihood for 75% of the earth’s land surface. The river ecosystem is formed the people. The water makes the area around the river fertile. by the interaction between river biota and their hydro- Since Long leng is primarily an agricultural district, the Dikhu geochemical environment. It is characterized by the River serves as a lifeline to its people. continuous transport of various substances, such as organic matter and the nutrients, from the soils of the drainage MATERIALS AND METHODS basin to the river and from there, downstream with the flowing water. River ecosystems are adapted to the natural Study Area hydrological regime and many components of these systems rely on floods for the exchange, not just of Nagaland is dissected by a number of seasonal and perennial water, but also energy, nutrients, sediments and living rivers and rivulets. Of the rivers, Dhansiri, Doyang and Dikhu organisms (Acreman, 2000). flow westward into the Brahmaputra. Dikhu River is one of the most prominent rivers of Nagaland. River Dikhu, which *Corresponding author: Lanuyanger Longchar, has a total length of about 160 km, originates from Nuroto Hill Department of Zoology, Nagaland University, Lumami- 798627, area in Zunheboto district. The river flows across the India. Mokokchung and the Longleng districts. 7626 Asian Journal of Science and Technology, Vol. 09, Issue, 02, pp.7625-7629, February, 2018 The main tributaries of river Dikhu are Yangyu of Tuensang trees and shrubs. The watershed properties of the river include district and Nanung in the Langpangkong range in mainly agricultural runoffs. Mokokchung district. Sampling site – 5 Changtongya Longleng Study Sites Site V is located midstream and doesn’t not have any For the present investigation, five sampling sites were selected adjacent farmland but it consists of short shrubs. It has a on the basis of accessibility and vegetation. The description of stretch of 1.68 km and width varying from 7.56 m to 33.29 m. study sites is given as under: The watershed properties of the river include mainly runoffs from adjacent soil and upstream agricultural runoffs. Sampling site –1: Longmisa Noksen Current/Flow Site I is located upstream. It has pebbles, sand and hard rock bed with vegetation covering at both sides of the river. It also The units that are typically used to express discharge include has nearby agricultural lands and tree plantations. The land use m³/s (cubic meters per second), ft³/s (cubic feet per second or pattern includes agricultural farmland and plantation. The cfs) and/or acre-feet per day (Dunne and Leopold, 1978). A watershed property of the water includes agricultural runoff. commonly applied methodology for measuring, and There were also no visible sources of waste disposal. It has a estimating, the discharge of a river is based on a simplified stretch of 2.18km and width varying from 9.56 m to 40.29 m. form of the continuity equation. The equation implies that for any incompressible fluid, such as liquid water, the discharge (Q) is equal to the product of the stream's cross-sectional area (A) and its mean velocity (), and is written as: = where Q is the discharge ([L3T−1]; m3/s or ft3/s) A is the cross-sectional area of the portion of the channel occupied by the flow ([L2]; m2 or ft2) is the average flow velocity0 ([LT−1]; m/s or ft/s) RESULTS Average monthly discharge (m3sec-1) were calculated for five study sites in Dikhu river. Help was sought from the Meterological Department in context with the monthly rainfall, vapour pressure and water velocity. Variable trends in flow measurements were recorded in the flow, which is depicted in Table 1 & Figure 1. At site 1, the minimum flow was recorded in the month of Dec’14 (0.2 cusecs) during the tenure of Sampling site – 2 Longmisa- Chuchu research from Nov’14 to October ’16. The peak flows were recorded in summer months with highest value of 9.53 cusecs Site II is located upstream. It has a stretch of 898.87 m and in May’15 and 9.23 cusecs in Jun’16. Flow duration width varying from 12.56 m to 32.29 m. It has pebbles, sand parameters and curve is depicted in Table 2 and Figure 2. At and hard rock bed with vegetation covering at both sides of the site 2, the minimum flow was recorded in the month of Dec’14 river. It also has nearby agricultural lands and tree plantations. (0.21 cusecs) during the tenure of research from Nov’14 to The land use pattern includes agricultural farmland and October ’16. The peak flows were recorded in summer months plantation. with highest value of 9.02 cusecs in July’15 and 9.34 cusecs in Jun’16. Flow duration parameters and curve is depicted in Sampling site – 3 Longkong Table 3 and Figure 3. At site 3, the minimum flow was recorded in the month of Nov’14 to Jan’14 (0.03 cusecs) Site III is located upstream. It has a stretch of 1.48km and during the tenure of research from Nov’14 to October ’16. The width varying from 8.56 m to 42.29 m. The area is composed peak flows were recorded in summer months with highest of pebbles, sand and hard rock bed with vegetations covering value of 0.43 cusecs in Jun’15 & July’15 and 0.47 cusecs in both sides of the river. The main types of vegetation include Jun’16. Flow duration parameters and curve is depicted in trees and shrubs. The watershed properties of the river include Table 4 and Figure 4. At site 4, the minimum flow was mainly agricultural runoffs. recorded in the month of Nov’14 & Jan’14 (0.03 cusecs). The peak flows were recorded in summer months with highest Sampling site – 4 Changtongya Yaongyimsen value of 0.43 cusecs in July’15 and 0.48 cusecs in Jun’16. Flow duration parameters and curve is depicted in Table 5 and Site IV is located upstream. It has a stretch of 1.88 km and Figure 5. At site 5, the minimum flow was recorded in the width varying from 7.56 m to 39.29 m. The area is composed month of Dec’14 (0.3 cusecs). The peak flows were recorded of pebbles, sand and hard rock bed with vegetations covering in summer months with highest value of 14.295 cusecs in both sides of the river. The main types of vegetation include 7627 Asian Journal of Science and Technology, Vol. 09, Issue, 02, pp.7625-7629, February, 2018 May’15 and 13.845 cusecs in Jun’16.