22nd IAHR-APD Congress in Sapporo| Online
September 15-16, 2020
A comprehensive intergrated management approach for water resrources management
Minh Ngoc Trinh, VNU Hanoi University of science
Introduction

The studied area

- Comprehensive management not only involves the management of natural systems, but also requires coordination of human activities that create water demand,
identify land use and create products that cause waste of water. Access to integrated management and sustainable development must take into account the waterbalance components, development activities and impacts in each region, multi-purpose use, multi-sectoral linkages, and connection between human society and nature(Figure 1).
- Programs and projects have been implemented with a system of vulnerable indicators combined using hydrological models, information systems and multi-criteria
analysis. This method is valuable to assist in making decisions which include stakeholder agreements, social awareness, and coordination among decision makers. Thatis the use of the vulnerability assessment framework and vulnerability indicators in integrated management approach at basin scale.

The Thach Han River: length: 150km, basin area: 2660 km2.
Based on the topographic elevation criteria, the study area is divided into 4 regions, and 12 subregions (based on the criteria of rainfall, discharge, groundwater level, water quality andpopulation density).
K1- the low mountainous area upstream Thach Han River including K11, K12 and K13 subregions
K2 - the middle area of Thach Han River including K21, K22 and K23 sub-regions
K3 - low mountainous region of Cam Lo River basin including K31, K32, K33, K34 sub-regions
K4 - downstream delta area of Thach Han River including K41, K42, K43, K44 sub-regions.

Figure 1. The relationship between vulnerability assessment and IWRM process.

Results
Description of key terms and methodology- Water resources vulnerability: can be defined as “the weaknesses of the water resources system make it difficult for the system toperform its functions in the face of socio-economic system and environmental changes”. Therefore, water resources vulnerability is
considered in two issues: (1) the exposure of the water resources system to pressures at the river basin scale, and (ii) the capacity ofthe ecological system and society can cope with threats to the healthy functions of a water resource system.
- Indicators:
Indicators may be based on physical, chemical or biological measurements associatedwith the quality of natural resources or the environment. They can generalize some
aspects of the environment, natural resources or human activities.
-Methodology: The author applies the method of assessing water vulnerability of UNEP
for Thach Han river basin
Figure 2. Information levels and indicators tower

The vulnerability of a river basin can be expressed as:
VI = f (RS, DP, ES, MC)
1. Resource stress (RS): the quantity and quality of water resource:(a) Water stress parameter(b) Water variation parameter

2. Water development pressure (DP):(a) Water exploitation parameter

3. Ecological health (EH)(a) Water Pollution parameter
𝐖𝐖𝑬𝑯𝒑 = 𝐖𝐑𝟎, 𝟏𝟎
𝑬𝑯𝒑 = 𝟏All sub-regions : range from 0, 4 - 0.7. Although the whole basin is generally in good condition (water availability is abundant), theamount of clean water provided for each sub-region is almost sufficient, the amount of water provide to other industries relatively).
The sub-regions K13, K31 and K32 are affected the lowest vulnerability in the whole basin. The reason is due to this area receiving
abundant water every year is plentiful and under water pressure for water use industries, the demand for clean water is not goodpeople in the area. The remaining basins are under high pressure, so efforts are needed to build a mechanism to provide technical andpolitical assistance to alleviate these pressures. Sub-region K41 with a vulnerability of 0.62, which near the sea so that the hydrometeorological elements are more variate than the other sub-regions, so the demand for water and its impacts to water resources has asignificant impact on the development of water resources in the region. The sub-regions K42 and K43 are all coastal plains ormidland, water resources are susceptible to salinity or pollution due to civil activities and economic development, the status of poor
environmental sanitation. The remaining sub-regions are all highly vulnerable, this is one of the numbers alarming managers toimplement appropriate development policies suitable for each region.
The author proposes a number of solutions to manage water resources issues for the sub-regions as follows:-Regionstudied
1 (The upland
mountainous area of ​upstream Thach Han river - K1). Low economic development level, limited underground
Theareawater. It is necessary to build more water collection works and reservoirs to store surface water for the dry season. Water collection
facilities are located in river and lake beds, with sufficient depth to facilitate the arrangement of other auxiliary works.
- Region 2 (Middle area of Thach Han river - K2): fertile soil, is very convenient for cultivation crops, should encourage the cultivateof industrial crops, timber trees in combination with cash crops, food crops and develop farm economy, encouraged to build breeding
facilities hygienic environment, apply animal waste treatment by dry composting, and forest protection
Region 3 (lowland mountainous region of Cam Lo - K3 river basin)
average level of socio-economic development such as animal husbandry
and fisheries should be encouraged, develop the capacity of preserving andpropagating aquatic products, and at the same time, limit the excessive
exploitation of the allowed levels.
- Zone 4 (the lower delta of Thach Han river - K4) with relatively crowded
population, shallow groundwater level, change the farming season
structure. It is essential to grow suitable crops such as crops demanding lesswater (corn, peanuts, etc) in the dry months andadjust the productionseason and change farming techniques. For water sanitation, it is necessary
to build a system of rainwater drainage systems that are reasonable andrenovate and treat waste water by natural constructions such as biologicallakes and wetlands in order to combat minor floods (in May and June).

(b) Safe Drinking Water Inaccessibility parameter(b) Ecosystem Deterioration parameter(𝑾𝑹 < 0,10)

𝐸𝐻𝑒𝐴𝑑=𝐴(𝐖𝑹 ≥ 0,10)

4. Management capacity (MC)(a) Water Use Efficiency parameter(b) Improved Sanitation Inaccessibility
parameter(c) Conflict Management Capacity
parameter:

Resultsoverall capacity in dealing withtransboundary conflicts - caculated the wholebasin sociological investigations
Where: VI = Vulnerability index; R = per capita water resources (m3 .person-1); CV = the coefficient of variation of precipitation over the last 50 year; WRs= Total water supply (capacity); WR = Totalwater resources (m3); WW = total wastewater discharge (m3); Ad= land area without vegetation coverage (km2); A = total land area (km2) ; WE = GDP value produced from 1 m3 of water; WEWM =mean WE of selected countries; Pd= population without access to improved sanitation; P = total population.

The integrated management of water resources for basins is an effective management method that has been studied and applied bymany countries. Assessing the vulnerability of water resources to a basin is a scientific basis for policy makers, managers, and experts
to access and exploit information on water resources related to the decision making of environmental and natural resource protection
policies.
References:- National Agency for Science and Technology Information, (2015). Intergrated water resrouces management, Water resources management situation in Vietnam. Hanoi.
- EnviroGRIDS - FP7 European project, (2012). Integrated water resource sustainability and vulnerability assessment. EnviroGRIDS_deliverableD5.8, 45p.
- UNDP, (2009), Methodologies guidlines, Vulnerability assessment of freshwater resources to environment changes, Thailand.