MRC-Water Quality Monitoring Network (WQMN) Thailand Revision Consultant Report Prepared by Wijarn Simachaya, Ph.D. Submitted to Thai National Mekong Committee (TNMC) And Mekong River Commission Secretariat (MRCS) October 2003 Table of Contents Content Page Introduction and Objectives 3 Existing National Mekong Water Quality Monitoring of Thailand 5 Removal of the Secondary Sampling Stations 9 Proposed New Sampling Stations 11 Water Quality Criteria/Standards 12 National Institution on Water Quality Monitoring Programs 13 Conclusion and Recommendations 14 References 16 Figure 1 Water Quality Sampling Station of the LMB 4 Figure 2 Existing Water Quality Sampling Stations under the Thai MRC-WQMN since 1985 6 Figure 3 The standard Information Recorded in the Fields 8 Table 1 Existing Sampling Stations of the Thai MRC-WQMN 7 Table 2 Water Quality Parameters and Methods for Analysis under Thai MRC-WQMN 9 Table 3 Classification of the Thai Tributaries in the Mekong River Basin 13 Table 4 The Revision of Sampling Stations of the WQMN Program of The Thai National Mekong Committee 15 Annex 1 Terms of Reference for the national WQMN 17 Annex 2 The existing sampling station profiles of the Thai MRC-WQMN 24 Annex 3 The existing sampling procedures of MRC-WQMN 96 Annex 4 The National Surface Water Quality Standards and Analysis Method 99 Annex 5 The Schedule Visits of the Survey team and Lists of Agencies Consulted 101 Annex 6 The templates of the proposed new sampling station 106 Annex 7 PCD’s monitoring sampling stations in the Mekong River Basin 122 2 MRC-Water Quality Monitoring Network (WQMN): Thailand Review 1. Introduction and Objectives Over the past several decades, the quality of receiving water bodies worldwide has been negatively impacted by various human activities. In the Mekong River Basin, clean water is critical. The health, economic well-being, and quality of life of most its residents are inextricably linked to the quantity and quality of the basin’s water resources. Surface waters in the Mekong have been used for meeting basic needs such as water supply, agriculture, industry, fishery, and wastewater disposal. Economic development of the basin has resulted in elevated levels of pollution from both point and non-point sources. Degradation of water quality in parts of the basin has evolved gradually over time until eventually becoming apparent and measurable. Thus, the foundation of effective water quality management is reliable water quality monitoring data and analysis. Water quality monitoring is the most crucial method to determining how much the receiving waterbodies have been impacted and can lead to the development of the affective means of controlling the pollution. In order to ensure that water quality throughout the basin is maintained at levels suitable to support various beneficial uses, the Water Quality Monitoring Network (WQMN) of the Mekong River Basin was established under the Mekong River Commission (MRC). The network has existed since 1985 in Lao PDR, Thailand and Vietnam, and since 1992 in Cambodia. Currently, the water quality monitoring is undertaken under the Environment Program (EP), MRC. The MRC-WQMN of the Lower Mekong Basin includes 98 sampling stations with 11 stations on the mainstream of the Mekong River and 87 stations on the tributaries of the basin and sub-basins of the member state countries. The sampling stations of the MRC-WQMN are shown in Figure 1. The sampling stations of the MRC-WQMN included the most important locations of the Mekong and Bassac Rivers in terms of transboundary issues and tributary locations that represented areas that have potential to be significantly impacted by upstream land uses and economic development. Specific guidelines or criteria for station selection were not considered. Since 1993, the MRC-WQMN has not reviewed nor has there been a systematic and comprehensive technical reviewed of the station network since it was originally set up. Additionally, with the implementation of the 1995 Mekong Agreement, the mandate of the MRC shifted with a greater focus being placed-on transboundary and basin-wide issues. The other core programs of the MRC, the: Water Utilization Program (WUP) and the Basin Development Plan (BDP) both require water quality information for planning purposes (Mekong River Commission, 2003). Under WUP, the rules for water quality are scheduled to be developed by the end of 2005. Information from the MRC-WQMN is needed to support the formation of the rules. The Mekong River Commission Secretariat (MRCS) has, therefore, contacted a local consultant to conduct a review of the existing sites and to recommend 3 additional sampling sites of the national water quality monitoring network. The Terms Of Reference (TOR) for the national WOMN review is attached in Annex 1. 4 The objectives of this paper are: - to review the existing water quality monitoring network for Thailand; and - to develop a set of recommendations for the national water quality monitoring stations profile of both the primary and secondary networks. 2. Existing Water Quality Monitoring Network of Thailand In Thailand, the Department of Water Resources (DWR, previously under the Department of Energy Development and Promotion) has monitored water quality at 18 sampling stations in the basin since 1985 with 3 sampling stations on the mainstream of the Mekong River and 15 sampling stations on tributaries. The objectives of sampling in the mainstream are to collect base line information and to assess the effects of the discharges from the main tributaries. The water quality in the mainstream was generally good due to the assimilative capacity of high river flows and low levels of pollution discharged from the tributaries (Sutabutr, 1996). The tributary sampling stations were established to determine depending upon the quantitative and qualitative contributions of different catchment areas in term of water discharges and point and non-point sources of pollution. Water quality analysis from 1972 to 1984 included 6 parameters: temperature, conductivity, pH, total hardness, alkalinity, and chloride. Since 1985, the WQMN of the Lower Mekong Basin (Lao PDR, Thailand and Vietnam) has sampled 23 water quality parameters including additional parameters such as calcium, magnesium, sodium, potassium, alkalinity, sulfate, total iron, nitrate nitrogen, nitrite nitrogen, ammonium nitrogen, total nitrogen, phosphate phosphorus, total phosphorus, silica, dissolved oxygen, COD (chemical oxygen demand), and pesticides contamination (organochlorine pesticides) in water and fish. The existing sampling stations of the national WQMN in Thailand are illustrated in Figure 2 and summarized in Table 1. The existing sampling station profiles of the Thai MRC-WQMN are illustrated in the templates as shown in Annex 2 5 Figure 2 Existing Water Quality Sampling Stations under the Thai MRC-WQMN since 1985 6 Table 1 Existing Sampling Stations of the Thai MRC Water Quality Monitoring Network Station Station Station Location River Name Measurement Code Name N E Water Water Water Sediment Meteoro Level Quality Quantity logical 010501 Chaing Sean 20-16-24 100-05-00 Mekong / / / / / (mainstream) 013101 Nakhon 17 23 54 104 48 12 Mekong / / / / / Phanom (mainstream) 01380 Khong 15 19 06 105 30 00 Mekong / / / / / Chaim (mainstream) 050104 Chaing Rai 19 55 06 99 51 00 Mae Kok / 290102 Ban Tha 17 51 42 103 46 48 Nam / / / / / Kok Daeng Songkhram 310102 Na Kae 16 55 42 104 41 48 Nam Kam / / / / 380134 Rasi Salai 15 20 06 104 09 42 Nam Mun / / / / 380103 Ubon 15 13 18 104 51 42 Nam Mun / / / / / 380127 Kaeng 15 14 24 105 14 54 Nam Mun / / / / Saphu 370122 Ban Chod 16 21 00 102 57 48 Nam Chi / / / / 370114 Ban Kok 16 20 49 102 58 12 Nam Chi / / / / / 370104 Yasothon 15 46 54 104 08 30 Nam Chi / / / / 380903 Ku Phra Ko 15 34 12 103 49 24 Nam Sioe / / / / Na 370299 Nam Pong 16 46 48 102 37 41 Pong / / / 371499 Lam Pao 16 20 06 103 35 00 Lam Pao / / / / 380699 Lam Dom 15 12 42 105 25 48 Lam Dom / / / Noi Noi 371203 Ban Tad Ton 15 57 30 102 01 48 Nam Chi / / / / / 380133 Ban Som 15 01 06 102 17 12 Nam Mun / / / / DWR assigned the Regional Hydrological Office to take the samples under the MRC-WQMN program. The standard sampling procedures have distributed to the Regional Hydrological Office are detailed in Annex 3. It can be concluded that the procedures of water quality monitoring under the MRC-WQMN are different from the Thai procedures that are set out in the National Surface Water Quality Standards and that follow the Standard Methods for the Examination of Water and Wastewater as described in Annex 4. DWR also monitored the amount of sediment in terms of suspended sediment at each water quality sampling station in the river using the US DH-48 Depth- Integrating Hand Samples. Three verticals for depth-integrated sampling have been taken on a weekly basis during the wet season and on a bi-weekly basis during the dry season for a total amount of at least 30 times/year. The standards information recorded in the field for each sample included location, code number, date and time, collector name, gauge height and water temperature. The standard information recorded in the fields is shown below: 7 Figure 3 The Standard Information Recorded in the Fields In general, rivers and streams are dynamic systems and their physical, chemical and biological properties vary from time to time. The selection of water quality monitoring stations depends on the purpose of the study as well as on the characteristics of the receiving waters such as river flows, distance from riverbank, river morphology, river cross section, point source discharges, etc. If it is possible, more sampling stations and more samples at each station are preferred. Grab samples are usually taken as part of a river or stream monitoring program at the middle highest zone flows of the stream and at depth.