GIS Approach to Small Tanks Mapping Mineriya,Giritale and Parakrama Samudraya Catchmant

Small Tanks Identification and Mapping through GIS

Minneriya, Giritale and Parakrama Samudraya Catchment Area

Let not a single drop of water go waste into the sea without benefiting the world ( King Parakramabahu, 12 Century AD).ObjectivesIdentify and mapping physical setting and distribution of small tanks A glance through the 1 inch to 1 mile (1:63,360) topographical maps of the Survey Department shows the physical location of these small tank systems and many small tanks are abandoned with the scale and the problems with scale of the Aerial Photographs, Classification of the map. We need to identify the village level small tanks to reawakening the agriculture based civilization and Hydraulic SocietyTo protect the ecosystems for environmental sustainability.Give the solution for natural disasters (Drought, Flood , Elephant Human Conflict)

DefinitionSmall tanks in Sri Lanka are with an irrigated command area of 80 ha (1 ha= 2.47acres) or less, as defined by the Agrarian Services Act No. 58 of 197A glance at the 1 inch to 1 mile (1:63,360) topographical maps of the Survey Department shows the physical location of these small tank systems, which are usually located within the first or second order inland valleys, or the ephemeral streams of the dry zone of Sri Lanka.Background InformationTotal estimated active and inactive small tanks based on one inch sheet is 18,387 According to John Keen Map shows five categoriesRehabilitated/ Re-constructedNon-rehabilitated tanksRecently Rehabilitated tanksActive Village tanksInactive Village tanks

Objectives of Small TanksPaddy CultivationProtect Water LevelPart of EnvironmentDrinking Water Facility for AnimalsProtect Water Stream to Provide for Small Tanks

Importance of Small Tank SystemEcological SocialEconomicalCultural

Ground Water LevelPaddyFishingFarmersSmall tank surface storage systems provided the lifeblood for human settlement and existence in these areas. The highly variable nature of rainfall combined with high evaporation rate for a greater part of the year, and the paucity of readily accessible groundwater in this hard rock region meant that no stable human settlement would have been possible without recourse to the storage of surface water in small tanks.ElephantSolution for ..DroughtDisaster mitigationHuman Elephant ConflictEnhancing the potential for improving productivityImproving tank fishing and animal husbandryHealth issues (Cadmium, Kidney failure and Malaria)

Distribution of Utilized and Abandoned Tanks (Main)AreaNumber of TanksActive %Inactive %Rajarata (North Central)4,0175248Ruhunu (Southern)1,4104654Wayamba (North Western)6,4636535Uthuru (Northern)1,4144357Total13,304Source: Small Tank Distribution and location (CR Panabokka)Project Area Information

Existing Data Source-1 inch Topographic MapsMinneriyaGiritaleParakrama Samudraya

3D View of the Minneriya

MethodologyIdentification Based on Satellite Image

Position/Location of TanksGPS NavigationSample Survey/Field ObservationDevelopment of Spatial Data Base Final Map PreparationSatellite Image

Visual Image Classification

Water AreaStreamDamDried Area

Shape

Active TankInactive TankImage Classification

Number of Small Tanks IdentifiedGN DivisionNo of Small Tanks Minihirigama46Ihakuluwewa111Moragaswewa08Katukeliyawa06CP Pura03Sidikanda-Nikawewa03Agbopura01Diyabeduma 07Kalahagala40Sinha Udagama08Samudragama01Sirisangabopedesa02Ethumalpitiya04Nissankamalapura03Ganangolla01Redevoroya01Chethiyagirigama01Henkolawewa01Agbopura01Samagipura01Batgampattuwa01Total250

Sample Survey (Minihirigama GN Division)

Name of TankBeddapanwilaDambagaha UlpathaGonamaleIrige WewaIriheoyaKatukeliyawaKudurugaswewaMakalawewaNagalakandaNika WewaRatmalewewaRotawewaRotawewa/ BatuwewaSaranagama WewaThambala WewaGPS Navigation

Identified LocationsSample Survey ResultsIdentified the location of Tanks and validated Tanks missing from the existing Maps Identified from the Survey 3 out of 15 Tanks shown in Survey MapsNeed to survey with community supportGuide the Community and obtain the correct information

Sustainable irrigation and water management technologyExpected Cascading SystemResultsustainable irrigation and water management technology to meet the challengeof recurrent water shortages and drought conditions in a seasonally dry environment.Existing Tank System

1234Classification of Small TanksFully Damaged Tank Rotawewa-Batuoya

Dried Tank Sudukanda Wewa

Abandoned Tank Gonamale Wewa

No repairs needed Beddpanwila

Good Condition Thambalawewa

Small Tank (Pond) Saranasirigama

Live Status report

Mapping of Small Tanks

Spatial Data Validation

Preparation of Spatial DatabaseTanksLand Use an Land CoverContourStream NetworkPaddy LandCanal SystemOther Features

GN Level Resource Maps

Identification of Irrigation System for Planning

High CostPrioritization of Construction Based on Spatial Database Medium Low CostNew Construction

to protect Nature.

Next StepTo Survey all Tanks (selected areas)Mapping all Tanks(selected areas)Prepare GND Level Resource MapsDevelopment of Spatial Database

Survey Team

Thank You