Integrated Modelling in the Mekong River Basin with ewater Source. Rachel S. Blakers Juanita Moolman

Transcription

1 Integrated Modelling in the Mekong River Basin with ewater Source Rachel S. Blakers Juanita Moolman

2 Context The Mekong is a trans-boundary river in Southeast Asia Flows through China, Myanmar, Laos, Thailand, Cambodia, Vietnam Rapidly growing economies and populations Myanmar China Laos Dams and hydropower projects have significant impact Basin area 795,000 km 2 Thailand Cambodia Viet Nam

3 Mekong River Commission (MRC) Established in 1995 by the Mekong Agreement Inter-governmental agency that works with the governments of Cambodia, Laos, Thailand and Vietnam Joint management of shared water resources and sustainable development of the Mekong River. MRC strategic plan says that basin development should follow Integrated Water Resources Management (IWRM) principles.

4 Introduction Present two Integrated Water Resources Management (IWRM) projects underway in the Mekong River Basin: Procedures for Water Use Monitoring (PWUM) Council Study Demonstrate alternative approaches to integrated modelling using Source: PWUM model built entirely using core Source modules Council Study uses Source as an integrator of other models and extends the Source framework via plugins

5 Procedures for Water Use Monitoring (PWUM) Aim: ensure that the use of the water resource is reasonable and equitable across the Member Countries of the Mekong River Basin focus on the water use issues which may affect the Mekong mainstream provide general water use information on a country by country basis requires understanding of water use 3 pilot projects - Laos, Thailand and Cambodia China Myanmar Thailand Cambodia Viet Nam

6 Procedures for Water Use Monitoring pilot catchments in each Member Country to confirm the procedure establish a baseline Nam Kam Xedone Stung Pursat extend the methodology to provide general water use information on a country by country basis monitor impact of water use change on the Mekong mainstream training and mentoring

7 Procedures for Water Use Monitoring Xedone catchment Laos National Mekong Committee (LNMC) Nam Kam Xedone Stung Pursat

8 Xedone catchment model components Catchment inflow GR4J Landuse Rainfall, PET Gauge Observed flows Water Users and demands Hydropower, Agricultural/ Urban, Environmental Minimum flow requirements for hydropower Storages

9 Total water demand - Xedone

10 Water availability and demand Xedone and Nam Kam NamKam Xedone Xedone

11 MRC Council Study (CS) In December 2011, the MRC agreed in principle to a study on sustainable management and development of the Mekong river including impacts by mainstream hydropower projects Phase 1: Reference Scenario representative of physical/socioeconomic conditions in 2007 (Simulation period ) Phase 2: Development Scenarios: Pre-development, 2000, 2020, and 2040

12 The Role of Source in the Council Study IQQM IQQM to Source Converter KB KB SWAT Source ISIS DTT DTT 1. Replicate the IQQM flows, hydropower and water use 2. Provide water quality (sediment & nutrient) modelling: a) Route sediment and nutrient loads generated by SWAT through Mekong tributaries to the mainstream b) Model sediment and nutrient trapping in dams and reservoirs 3. Export results to the MRC Knowledge Base (KB) for scenario impact assessment

13 IQQM to Source Conversion Performed automatically via a plugin 174 nodes 1094 nodes 2019 nodes IQQM model Source model

14 Comparison of IQQM and Source Outputs Model outputs consistent to within < 1% relative bias Flow Hydropower at Kratiegeneration gauge (outlet at Dachaoshan of the Lower Dam Mekong) (Upper Mekong) IQQM Source

15 Reality Expectation Sediment & Nutrient Transport SWAT (Soil & Water Assessment Tool) produces catchment runoff, sediment and nutrient loads SWAT integration was challenging SWAT Source routing & fluxes SWAT sediment loads (cumulative) SWAT SWAT +/- Source routing Plugin to assist import

16 Reservoir Sediment & Nutrient Trapping Plugin Brune sediment trapping model - relates the reservoir capacity-inflow ratio to trap efficiency Linked nutrient trapping model Calibration hampered by data quality and quantity: Employed an annual mass balance approach. Location Estimated Sediment Trap Efficiency (Brune) Manwan Dam 67.2% Dachaoshan Dam 63.5% Xiaowan Dam 94.5% Nuozhadu Dam 94.5% Baseline Scenario Additional development scenario

17 Sample Simulation Results Sediment loads at Chiang Saen (outlet of Upper Mekong)

18 So how did Source help us? Source acts as the framework, integrating relevant water resources information from various origins so that the system can be modelled combines external model inputs to generate an integrated model which can then be used to extend modelling e.g. to include water quality integrates rainfall-runoff modelling and water use creates opportunities for capacity building becomes a centre point to facilitate transparency and consultation / conversation CLIMATE WATER QUALITY LAND USE ECOLOGICAL ASSETS DAMS & WEIRS IRRIGATION CITIES

19 Thank you Questions?