FIJI Navua River
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FIJI Navua River 1. COUNTRY INTRODUCTION and irrigation. Some small, low-lying islands and many villages rely almost exclusively on Description: groundwater and rainwater harvesting. The Fiji Islands comprise of 322 islands, of which Flooding regularly occurs throughout various a third are inhabited. The two main islands of parts of the country, where some larger towns Viti Levu and Vanua Levu have significant urban including Nadi and Ba, and Labasa have areas, with the capital city of Suva located in developed in highly flood prone areas. These the south east of the western main island of Viti floods can cause loss of life and significant Levu. The archipelago is comprised of volcanic damage to property and infrastructure as well peaks and uplifted oceanic sediments, as well as as disrupting economic activity and impacting coral and sand islands. on the lives of communities. Alteration to the Fiji is endowed with forest, mineral, fishery and floodplain for agriculture, logging, and the water resources and is one of the more developed progressive deforestation for agriculture may of the pacific island countries. Traditionally sugar cause flood peaking to become more extreme in exports and tourism have been the major source the future. of foreign exchange with sugar representing Drought is also a regular occurrence and a one-third of industrial activity. Economic serious concern, with limited storages. The development has been restricted in recent times 1998 drought, affected over half of the country, due to the ongoing issue of uncertain land where no significant rainfall fell for more ownership rights and recent political instability than seven months, and food was distributed which has dampened investment and restricts by the government to 105,000 people. On development opportunities. Gold mining has small, low-lying islands water supplies are made a valuable contribution to Fiji’s economic particularly susceptible to extended dry periods, development, with good prospects for additional and groundwater resources are vulnerable development of mineral resources including to over-abstraction and contamination from copper and aluminium in the coming decades. inappropriately located surface activities. In the last 10 years there has been a rapid Industrial pollution, urban drainage and sewage development of mineral water abstraction and are cause for concern on large islands in the bottling, with bottled water exports to markets in urban and peri urban areas. North America. It has been identified that 11% of the land is Surface water is used as the main source of water arable and used for cultivation while 5% is supply for all cities and major towns on the taken up by permanent crops, such as renewable larger, high islands of Fiji, as well as for industry forestry. The remaining 84% comprises of native CATALOGUE OF RIVERS FOR PACIFIC ISLANDS Page 36 forests, grasslands, urban area and other non- Other islands and island groups, which represent arable land, (CIA World Fact book 2009). 12.5 % of the land area and house some 16 % of the population, include Taveuni southeast The country’s electricity supply is produced from off Vanua Levu and Kadavu Island, south off a mix of hydropower schemes, diesel generation Viti Levu (the third and fourth largest islands and other renewables. Recent data indicates that respectively). The Mamanuca Group (just off 59% of electricity was produced from renewable Nadi) and Yasawa Group (to the north of the sources (2009, FEA), specifically hydropower Mamanucas), are popular tourist destinations. including 1% solar and wind with the remainder The Lomaiviti Group located to the east of Viti 40% coming from diesel generation. Levu, includes the island of Ovalau, and is home An estimated 70% of the population has access to Levuka, the former capital and the only major to treated reticulated water; however continuity town on any of the smaller islands. The remote of supply remains a problem, particularly during Lau Group is located in the Koro Sea to the east drier months. of Viti Levu and located near Tonga, from which Two catchments on the main island of Viti Levu it is separated by the Lakeba Passage. supported by Pacific HYCOS are profiled here, Two outlying regions are Rotuma, 400 km to the Rewa and the Navua River systems which the north, and the uninhabited coral atoll and have significance as two of the three largest rivers cay Ceva-i-Ra or Conway Reef, 450 km to the in Fiji. With the support of European Union southwest of main Fiji Islands group. Culturally funding, SOPAC has implemented hydrological conservative Rotuma with its 2000 people on monitoring and flood warning and forecasting 44 sq km geographically belongs ethnically to systems in both catchments. Polynesia and enjoys relative autonomy as a Fijian dependency. 2. GEOGRAPHIC Map of Fiji Islands The Fiji Islands are located about 4,450 km southwest of Honolulu and 1,770 km north of New Zealand. Of the 322 islands and 522 smaller islets making up the archipelago, about 106 are permanently inhabited. Viti Levu, the largest island, covers about 57 % of the nation’s land area, and contains some 69 % of the population. Viti Levu hosts the two official cities (the capital Suva, and Lautoka), along with other major towns, such as Ba, Nasinu, and Nadi (the location of the international airport). Vanua Levu, 64 km to the north west of Viti Levu, covers just over 30 % of the land area and significantly less populated being home to only some 15 % of the population. Its main towns are Labasa and Source: CIA World Factbook, 2011 Savusavu. Both islands are mountainous, with volcanic peaks rising up to 1,300 m on Viti Levu, Viti Levu, Geology and Land Use are shown covered with tropical forests, especially on the below. The map of the main Island also shows eastern side, where heavy rains fall resulting in the extent of the HYCOS study catchments of more dense tropical forest. Lowlands on the the Rewa River, Fiji’s largest and the adjacent but western portions of each of the main islands are much smaller Navua River. sheltered by the mountains and have a well- marked dry season favorable to crops such as sugarcane. Page 37 FIJI Map of Viti Levu showing the Navua and Rewa catchments Source: Google maps and SOPAC 2010 Geological map of the Viti Levu Source: (http://www.mrd.gov.fj/gfiji/geology.html) CATALOGUE OF RIVERS FOR PACIFIC ISLANDS Page 38 Land use map of the Island of Viti Levu Source: MRD 1991 3. CLIMATIC The Climate Service Division of the Fiji Fiji enjoys a tropical maritime climate without Meteorological Service located in Nadi great extremes of heat or cold. Day-time sea is responsible for meeting Fiji’s needs for breezes regularly blow across the country being climatological data and for promoting the generally light or moderate; strong winds are effective use of this data for weather forecasting. far less common and are most likely to occur It is the national repository for climatological in the period June to November when the trade data and is responsive to user enquiries for winds are most persistent. However, tropical preparation and supply of data products cyclones and depressions can cause high winds, including aviation and marine forecasting for especially from November to April. Due to the region. The Nadi - Tropical Cyclone Centre the influence of the surrounding ocean the was officially designated by WMO in June average annual temperatures change only about 1995 as a Regional Specialised Meteorological 2º to 4ºC between the coolest months (July Centre (RSMC) with activity specialization in and August) and the warmest months (January tropical cyclones tasked to provide “first-level” to February). Around the coast, the average information in tropical cyclones (i.e., basic night-time temperatures can be as low as 18ºC information covering the tropical cyclones’ and the average day-time temperatures can be present and forecast position, movement and as high as 32ºC. Past records, however, show intensity) in the South-West Pacific Ocean. extreme temperatures as low as 8ºC and as high Page 39 FIJI as 39.4ºC have been recorded in Fiji. Rainfall rainfall. Low lying urban centers (Nadi, Navua, is highly variable and mainly orographic, with Rewa and Ba), on Viti Levu, are situated near the the main islands having pronounced dry and mouth of four of the main rivers and so are flood wet zones. Little climatic differentiation occurs prone. Labasa in Vanua Levu is also regularly on the smaller islands. Fiji experiences a distinct impacted by flooding. Localised flash flooding wet season often bringing cyclonic activity, during the wet season (November to April) is sometimes with great severity (November to quite common. Storm tides and heavy swells April) and a dry season for the remaining year, can cause flooding of low-lying coastal areas controlled largely by the north and south especially during the passing of a severe cyclone. movements of the South Pacific Convergence Droughts in Fiji are are experienced periodically Zone, the main rainfall producing system for the and can be severe especially on the outer islands. region, with much of the rain falling in heavy A strong ENSO, El Niño event is most likely and brief local showers. Annual rainfall in the to result in a major drought over the country, dry zones averages around 2,000mm, whereas as happened during 1982/83 and 1997/98 El in the wet zones, it ranges from 3,000mm Niño years. However, even in a “normal year” around the coast to in excess of 5,000mm at the the rainfall in the “dry zones” of the country mountainous sites. can be so low and a few months of an extended dry period can cause a drought impact in some Flooding in Fiji is experienced annually.