Spatiotemporal Hydrological Modelling with GIS for the Upper Mahaweli Catchment, Sri Lanka

Sustainability of water resources is imperative for the continued prosperity of Sri Lanka where the economy is dependent upon agriculture. The Mahaweli river is the longest in Sri Lanka, with the upper catchment covering an area of 3124 sq .km .. The Mahaweli Development programme, a major undertaking in the upper catchment has been implemented with the aims of providing Mahaweli water to the dry zone of the country through a massive diversion scheme and also for generating hydropower. Under this programme, seven large reservoirs have been constructed across the river and large scale land use changes in the catchment have occurred during the last two decades. Critics now say that the hydrological regime has been adversely affected due to indiscriminate land use changes and, as a result, river flows have diminished during the last two decades, thus jeopardising the expectations of this massive development programme. Reforestation programmes have been recommended because of the benefits of forest in resource conservation and also the water derived from fog interception. Selection of the best sites for these forest plantations for maximum benefits, especially in terms of water yield from fog interception has the utmost importance. This created the need for a comprehensive model to represent the hydrology and to simulate the hydrological dynamics of the catchment In conceptual terms, GIS is well suited for modelling with large and complex databases associated with hydrological parameters. However, hydrological modelling efforts in GIS are constrained by the limitations in the representation of time in its spatial data ,structures. The SPANS GIS software used in this study provided the capability of linking spatially distributed numerical parameters with corresponding tabulated data through mathematical and statistical expressions while implicitly representing temporality through iterative procedures.The spatial distribution of land use was identified through the supervised classification of IRS-IA LISS II imagery. Daily rainfall data for a 30 year period and corresponding gauging locations derived from GPS were managed and retrieved through a Lotus 1-2- 3 database. The fog interception component was estimated based on elevation and the monsoon season. Hydrological processes such as interception and evapotranspiration were derived from individual sub models and finally combined within the overall hydrological model structure. The model was run with daily time steps on numerical 'values of each quad cell of the thematic coverage. The information on flow derived from the model was depicted as a series of thematic maps in addition to the time series of numerical values at subcatchment and catchment outlets. The results confirmed that the model is capable of simulating catchment response of the UMCA successfully. The time dimension was accommodated through a senes of non-interactive REXX programmes in developing the customised version of the model. It is concluded that the software architecture of SPANS GIS is capable of accommodating spatiotemporal modelling implicitly in its spatial data structures although changes in the model structure may necessitate considerable reprogramming. Sensitivity of the model for different spatial interpolation techniques was evaluated. Further, sensitivity of the model for the defined hydrological parameters, spatial 'resolution and land use was also assessed. The model is sensitive to land use changes in the catchment and it shows 15-35% annual increase of runoff when forests are converted to grassland. Further studies are required to develop a more detailed set of hydrological parameters for the model

Forage Composition and Quality of Tankbed Grassland Ecosystems in Sri Lanka; A Preliminary Study of “Tabbowa” Tank

Although, Sri Lanka does not have large natural lakes, the early settlers devoted their energy to build water bodies (tanks or reservoirs) in association with forest catchments to provide water for irrigation. The tank bed is a grassland area of the tank, which lies between the catchment forest and the present water level. In general, the tankbed has three major zones - lower, middle and upper - and in some seasons the middle and upper parts may be underwater. This tankbed area is dominated by grassland vegetation and is a valuable feeding ground for free-grazing livestock. The main objective of this study was to identify the common forage species and to investigate the nutrient composition of species most relevant to ruminant livestock in one of the larger tankbed grasslands in the country

Dry Matter Production and Nutritive Quality of Wild Guinea Grass (Panicum maximum) Grown Along Roadsides in Sri Lanka

Wild Guinea grass (Panicum maximum) was introduced into Sri Lanka in the 1820s for forage purposes and has now naturalised in most ecological zones, ecosystems and habitats including roadsides with the exception of hilly and semi-arid parts of the country. The enormous distribution of the grass throughout the country has contributed much to supplying livestock feeds, soil erosion control, and improvement of soil fertility. The objective of this study was to investigate the growth, dry matter (DM) production and nutritive quality of wild Guinea grass along roadsides in different ecological zones

TRADITIONAL TREE AND SHRUB FODDERS FOR LIVESTOCK FARMING IN SRI LANKA

A vast array of natural trees and shrubs are traditionally being used by livestock farmersdetermining the usefulness of them through their experience are traditionally using shrubs.These plants may be represented in writings over thousands years ago as fodder trees in Sri-Lankan traditional livestock farming systems. These range from short structure shrubs throughlarge trees which can grow to a height of 30m.Botanically they come under several plantfamilies and basically categorized 15 leguminous and non leguminous tree fodders and bothcategories are equally Important as foragesPremier reviews of the natural fodder trees and shrubs have been carried out in Sri Lanka byseveral investigators under several institutions. 'Those studies were mainly composed to regionalsurveys, laboratory analysis on the composition and adverse factors and simple feedingexperiments.Studies revealed that the most of tree and shrub leaves are rich in CP, Ca, Mg, and average in Pand S, low in Na and trace in Cu and Zn. The average Crude Protein (CP), Neutral DetergentFiber (NDF), Acid Detergent Fiber (ACF), Lignin, Cellulose and Total ash vary from 9.0 to28.1%,33.3 to 54.0%, 18.37 to 50.08%, 4.7 to 22.0%, 11.5to 24.8 and 4.6 to 14.7 respectively.There is a high variation in DCP (5.5 to 19.8%) and TDN (36.3 to 83.4%). In most of thespecies, In-vitro Organic matter Digestibility (IVOMD) value is between 45 to 55% while fewspecies show a value more than 55%,and less than 45% .In a nitrogen balance study, all the treefodder tested was able to maintain a positive nitrogen balance. Some natural tree fodder containsanti quality substances. Tannins are most popular substances, which occur in some tree leaves.Farmers currently overcome this problem by feeding mixtures of fodders, feeding in later stagersthat tannins are low in content and wilting or sun dryingLittle effort had been made to study and obtain information including production andconsumption under the natural habitats and their feeding limitations. Therefore increasedattention needs to given those as a team approach with all relevant institution

Effect of Different Additives on Fermentation Characteristics of Fodder Sorghum [\u3cem\u3eSorghum bicolor \u3c/em\u3e(L) Moench] Compared to CO-3 (\u3cem\u3ePennisetum perpureum \u3c/em\u3e x \u3cem\u3e Pennisetum americarnum\u3c/em\u3e)

Milk production plays a vital role to overcome the nutritional poverty in all aged groups of people. But there are many kinds of constraints to sustainable milk production in Sri Lanka. The biggest problem is high cost of feeding of dairy animals due to high price of compounded feeds, lack of knowledge on methods of low-cost feed supplementation and seasonal fluctuations in ruminant feed resources. Less availability of good quality green forages has led to low productivity from national dairy herd of Sri Lanka during the dry season (Premaratne and Premalal, 2006). Silage production is one of the most popular as well as cheap and effective method of forage conservation to increase the feed availability for dairy cattle during the dry season. Sorghum (Sorghum bicolor (L) Moench) and CO-3 (Pennisetum perpureum x Pennisetum americarnum) are some of the crop varieties which can be effectively used for silage making. Therefore, the objective of the present study was to find out the effect of different additives on fermentation characteristics of fodder sorghum and CO-3

INVASIVE MICRO FLORA AND FAUNA IN MAHAVELIWILDLIFE REGION

Invasive flora and fauna have been reported to spread rapidly threatening the biodiversity andeconomic value of natural and agricultural ecosystems in Sri Lanka, Mahaweli Wildlife Regionthat covers about 200,000 ha of land (protected areas as national parks, nature reserves andsanctuaries) in the dry zone has alsc affected by these flora and fauna, A preliminary survey wasconducted in Maduruoya, Minneriya, Wasgomuwa, Flood plain and Somawathiya nationalparks, Riverine and Minneriya/Girithale nature reserves and Polonnaruwa sanctuary to identifythe commonly listed invasive macro flora and fauna by the World Conservation Union (IUCN),Sri Lanka and their distribution in the region through field observation and personalcommunication,The results revealed that there WGIC 6 species of fauna (Tank fish-Hypostomus plecostomus,Thilapia-Sarotherodon mossambicus, Gient African snail-Achatinafulica, House rat-Ratus ratusand Feral buffalo-Buba/us bubalus, Snake skin gouramy - Trichogaster pactoralis ,Trichogaster pectotalis) and 8 species of flora (Water hyasinth-Eichornia crassipes, Salvinia-Salvinia mo/esta, Prickly lantana-Lantana camara, Podisinghornarang-Eupatorium odoratum,Mimosa invisa, Ipil Ipil-Leucaenec1 leucocephala, Hydrilla-Hydrilla verticil/ata and Illuk-Imperata cylindrica) out of 43 species of exotic invasive biota listed by the IUCN, Sri Lanka,The Tank fish out of 6 fauna species recorded in the study has not been recorded previously inthis region, It was also found that one plant species, commonly called as Agada(Xanthiumindicum) which is not in the IUeN list, were appeared to be major threats in this aspect in theregion. It was also observed that several invasive plant species had positive impacts on somefaunal groups such as insects, amphibians reptiles and birdsThis paper discusses the common invasive species and their impact on the biodiversity andeconomic value and legal issues and offer suggestions for further research in the region forsound wildlife management

Nutritive Value and Silage Quality in Fodder Sorghum (\u3cem\u3eSorghum bicolor\u3c/em\u3e), Maize (\u3cem\u3eZea mays\u3c/em\u3e) and Hybrid Napier (\u3cem\u3ePennisetum americarnum\u3c/em\u3e × \u3cem\u3eP. purpureum\u3c/em\u3e) Grown in Sri Lanka

For continuous genetic improvement of cows, nutrition and management conditions should be improved to allow cow to produce its inherited potential production. However, many farmers not pay desired attention on forage quality and one of the main reasons for the low productivity of dairy cattle is under nutrition. Therefore, production of high quality fodder varieties is vital for strengthening the dairy sector in Sri Lanka. Hybrid Napier var. CO-3 is widely used for cattle feeding in Sri Lanka. It is important to find out other forage varieties with maximum nutritive values and minimum anti-nutritive factors which can be used as a cattle feed. Sorghum is a crop for semi-arid regions in tropical and sub-tropical zones which can be grown successfully throughout the country both under irrigated and rain-fed conditions. In addition, it has shown a huge potential to produce high green fodder yields. Maize is one of the most important plants grown for fodder production in the world. It possesses most of the characteristics of an ideal type of fodder and forage plant. Hence, this field research was conducted to investigate the possibilities in use of fodder Sorghum var. sugargraze and Maize var. pacific 984 as green fodder and/or silage in Sri Lank