Impacts of economic activities to the water quality of hieu river in chau hanh commune, quy chau district, nghe an province

ACKNOWLEDGEMENTS I would like to express my great appreciation to Assoc Prof Dr Tran Quang Bao from Vietnam Forestry University, my research supervisor, for his enthusiastic encouragement and useful critiques on this research Without his thoughtful and patient guidance through every step of my research and her knowledge on how to correct and analyze the data I collected, this thesis could not be completed I also would like to say thanks to lecturers, who have taught us for more than years, and to the cooperation of Vietnam Forestry University and Colorado State University, especially, the faculty of Forest Resource and Environmental Management I would like to extend my gratefulness to Mr.Sam Van Thiet, the Chairman of Chau Hanh People’s Committe for accepting my research in Chau Hanh commune And, I would like to express my gratefulness to Mr Dang Manh Hung, the Head of Quy Chau Hydrology Station, Department of Natural Resources and Environment, Nghe An Province, Vietnam for providing information and documents Last but not least, I wish to thank Dr Bui Van Nang and Ms Nguyen Thi Ngoc Bich of the Center of Laboratory and Practice of Vietnam Forestry University for providing me with the measure instruments and helping me measure the indicators to complete my thesis Xuan Mai, 12th September, 2016 Student Tran Thanh Quang TABLE OF CONTENTS ABSTRACT 1 INTRODUCTION 2 RESEARCH OVERVIEW 2.1 Water quality indicators 2.2 Literature reviews STUDY AREA 3.1 Natural conditions 3.1.1 Geographic location 3.1.2 Topography 3.1.3 Climate 3.2 Socio-Economic Conditions 3.2.1 Economic characteristics 3.2.2 Demographic characteristics GOALS AND OBJECTIVES 4.1 Goal: 4.2 Specific objectives: METHODS 10 5.1 Data sources: 10 5.2 Data collection method: 10 5.2.1 Water sampling: 10 5.2.2 Analysis of water samples collected: 13 5.2.3 Interviewing: 16 5.3 Data analysis method: 16 RESULTS AND DISCUSSION 17 6.1 Flow characteristics of Hieu river in study area 17 6.2 Water quality 18 6.2.1 pH 20 6.2.2 Dissolved oxygen (DO) 20 6.3 Economic activities of study area in Hieu River 23 6.3.1 Agriculture and forestry 24 6.3.2 Industry 24 6.3.3 Trade and services 25 6.4 Efects of land use on water quality 26 6.5 Solutions to improve water quality and sustainable water use in the study area 29 6.5.1 Policy solution 29 6.5.2 Solutions on land use and land planning 29 6.5.3 Technical solution 30 CONCLUSION 31 REFERENCES LIST OF TABLE Table 5.1 Sampling position: 11 Table 5.2 Limit values for surface water quality parameters – Follow QCVN 08: 2015/BTNMT 12 Table 5.3 Interviewing information on economic activities on Hieu River in Chau Hanh commune: 16 Table 6.1 Some water indicator of Hieu river in Chau Hanh commune from the year 2008 to 2015: 17 Table 6.2 Analysis indicator of Hieu river in Chau Hanh commune: 19 Table 6.3 Characteristics of sample location 27 Table 6.4 Analysis of water indicators and sampling locations 27 LIST OF FIGURE Figure 3.1 Position of Chau Hanh commune Figure 5.1 Sampling positions 11 Figure 6.1.The analytical result of temperature from the year 2008 to 2015 17 Figure 6.2.The analytical result of average discharge from the year 2008 to 2015 18 Figure 6.3.The analytical result of suspended solids from the year 2008 to 2015 18 Figure 6.4 The analytical result of DO 20 Figure 6.5 The analytical result of TDS 21 Figure 6.6 The analytical result of TSS 21 Figure 6.7 The analytical result of BOD5 22 Figure 6.8 The analytical result of COD 22 Figure 6.9 Map of plant cover in study area 23 Figure 6.10 Analytical results of water indicators and sampling locations 28 ABSTRACT It has been widely accepted that there is a close relationship between the economic activities and water quality There have been some researches on this relationship about the economic activities and land use impact on water quality in recent years This study aims to analyze the influence of economic activities, especially the various land use types on the water quality of Hieu River in Chau Hanh - a commune in mountainous areas of Vietnam based on the water quality indicator data with the characteristics of riparian buffer The results indicated that there was significant correlation between land use in the riparian buffer and the water pollution The loss of plant cover is proportional to the increase in the level of water pollution The results can provide scientific reference for the local land use optimization and water pollution control 1 INTRODUCTION Water is a necessary resource and most important in river basin Although river water makes up only about 0.2 percent of all the fresh water on Earth, it plays a very important role Rivers are like roads They carry water, sediment, organisms and nutrients They also help drain rainwater and provide habitats for many species of plants and animals Today, water requirements more and more (both quality and quantity) but the amount of untreated waste water increasing so resulting in many areas, water resource was seriously polluted [1] Today in the world, hundreds of river catchment management organizations were established to integrated management of water, soil and other related resources in the river catchment to maximize the economic benefit and social welfare but without damaging the sustainability of environmental system in the catchment, maintain the environmental conditions for human life [2] Hieu river is one of the major rivers in Nghe An province Hieu river watershed located in the northwest of Nghe An province is a strategic location for economic development and national security of the province This is an important watershed in the Lam river system with an area of 5417 km2 [3] In recent years, the districts in Hieu river catchment are increasing resources for economic development with high growth rate and leading to the inconsequential use of water resource and create the risk of recession and water pollution more and more serious If no control and protect, in the near future, Hieu river will become a “dead” river [4] Therefore restoring the old situation of Hieu river and make measure to manage and protect the Hieu river catchment in a sustainable way, ensuring maximize economic benefit and social welfare but not harm the sustainability of environmental systems in catchment is a currently urgent problem Based on this basis, I proceed to implement the thesis project: “Impacts of economic activities to the water quality of Hieu river in Chau Hanh commune, Quy Chau district, Nghe An province” The thesis aim to assess the current situation of water quality and compare with landuse in Hieu river, thereby propose solutions for sustainable economic development associated with environment protection in study area 2 RESEARCH OVERVIEW 2.1 Water quality indicators Water quality management: Water quality can be thought of as a measure of the suitability of water for a particular use based on selected physical, chemical, and biological characteristics The measurement of water quality properties includes: - pH: The pH of water determines the solubility (amount that can be dissolved in the water) and biological availability (amount that can be utilized by aquatic life) of chemical constituents such as nutrients (phosphorus, nitrogen, and carbon) and heavy metals (lead, copper, cadmium, etc.) Excessively high and low pH can be detrimental for the use of water Pollution can change a water's pH, which in turn can harm animals and plants living in the water [5] - Dissolved Oxygen (DO): DO can tell us a lot about water quality The oxygen dissolved in lakes, rivers, and oceans is crucial for the organisms living in it As the amount of dissolved oxygen drops below normal levels in water bodies, the water quality is harmed and creatures begin to die off Dissolved oxygen in surface water is used by all forms of aquatic life; therefore, this constituent typically is measured to assess the "health" of lakes and streams [5] - Total Suspended Solid (TSS) and Total Dissolved Solid (TDS): environmental water may contain a variety of solid or dissolved impurities In considering waters for human consumption or other uses, it is important to know the concentrations of both suspended and dissolved solids The most common pollutant in the world is “dirt” in the form of TSS [5] - BOD: Biochemical Oxygen Demand (BOD) is a measure of the quantity of oxygen used by microorganisms in the oxidation of organic matter Many animals need high oxygen amounts to survive If the BOD is high, that means that microorganisms are using most of the Oxygen This situation makes it difficult for larger aquatic animals to survive However, if the BOD is low, there is an abundance of Oxygen which leads to good water quality The BOD is an important water quality factor that is directly related to the overall health of the water body [5] - COD: Chemical oxygen demand (COD) is a measure of the capacity of water to consume oxygen during the decomposition of organic matter and the oxidation of in-organic chemicals The chemical oxygen demand (COD) test is commonly used to indirectly measure the amount of organic compounds in water Applications of COD determine the amount of organic pollutants found in surface water (e.g lakes and rivers) or wastewater, making COD a useful measure of water quality [5] This study also focus on the riparian buffers Riparian buffers can be an important component to stream stability, pollutant removal, and maintaining stream health Ensuring the integrity of these features, and restoring previous buffers, can have a positive impact on water quality [6] 2.2 Literature reviews Research on River catchment in Vietnam was done quite early, especially the intensive research in the fields of: meteorology - hydrology, geomorphology topography… create foundation for water quality research in river catchment recently developed stronger Vietnam has a dense river network River with a length of over 10km total about 2732, comprising 13 large river systems with a total area of 10 000 km2 The 13 river basins, 10 of which are trans-boundary systems, cover 80% of the country’s territory Basins of the largest river systems, which include Red, Thai Binh, Bang Giang – Ky Cung, Ma, Ca, Thu Bon, Ba, Dong Nai and Cuu Long, account for 90% of the total river basins nationwide Each river basin has typical natural resources characteristics as well as water resources In practice, management approaches vary from one basin to another, which has a close linkage depending on socio-economic conditions, land use situation, environmental factors … [8] Water quality is affected by nature factors as well as human Human impacts on water resource not only changes the amount of water, but also alter the water balance components, hydrological regime of water and especially changing its quality It was explained that the majority of rivers and lakes in Vietnam is also the source of water supply and receiving public sewage, industry and agriculture The main types of economic activity that create largest influence on the change of quantity and quality of water resources are: demand for water for industrial and public needs, sewage dump, urbanization, building of reservoirs, irrigation and flood the dry land, the activities of agricultural and forestry production [7] Table 6.2 Analysis indicator of Hieu river in Chau Hanh commune: QCVN 08-MT: Sample Indica No Avera 2015/BTNMT Unit tor ge 10 11 12 27.2 27.5 27.2 27.8 27.5 27.3 27.2 27.2 27.5 27.5 27.3 27.2 A1 A2 B1 B2 27.4 - - - - Temp pH - 7.2 6.7 7.2 6.8 7.3 7.0 7.5 7.7 7.8 6.8 7.1 7.3 7.2 6- 8.5 6- 8.5 5.5- 5.5- DO mg/L 5.62 5.20 5.49 5.44 5.60 5.21 4.99 5.62 5.60 4.85 4.91 4.99 5.31 ≥6 ≥5 ≥4 ≥2 TDS mg/L 19.1 20.0 19.8 20.2 19.2 20.5 20.5 20.0 20.8 21.2 21.5 21.2 20.3 - - - - TSS mg/L 713 779 731 831 755 805 765 740 723 874 860 895 789 20 30 50 100 BOD5 mg/L 31.1 29.2 31.9 33.2 30.5 34.4 35.1 33.8 34.3 34.7 38.8 35.5 33.5 15 25 COD mg/L 105 112 109 131 97 112 109 110 117 143 121 135 118 10 15 30 50 C Time: 17th August, all samples were taken in hours 8.00 am – 10.00 am; Weather conditions: Rainy 19 Analysis of each indicator: 6.2.1 pH pH parameter of Hieu river water in Chau Hanh commune ranged from 6.7 to 7.8, averaging about 7.2, satisfy with required quality of surface water for domestic purpose 6.2.2 Dissolved oxygen (DO) Measured values of DO in study area are shown in the following graph: Dissloved Oxygen 5.69 5.62 5.2 5.44 5.6 5.21 5.62 5.6 4.99 4.85 4.91 4.99 DO (mg/L) 1 10 11 12 DO A1 - QCVN A2 - QCVN B1 - QCVN Linear (DO) Sample Figure 6.4 The analytical result of DO The result show that: on average, DO value of Hieu river water in study area is satisfy with the A2 standard (water quality for domestic purpose) However, after flow into Chau Hanh commune, DO value tend to decrease from 5.62 mg/L to 4.99 mg/L 6.2.3 Total dissolved solids (TDS) Measured values of TDS in study area are shown in the following graph: 20 Total Dissolved Solids 22 21 TDS (mg/L) 20 20.8 20.5 20.5 20 19.8 20.2 21.2 21.5 21.2 20 19.2 19.1 19 18 17 TDS 16 Linear (TDS) 15 10 11 12 Sample Figure 6.5 The analytical result of TDS The result show that: average TDS value of Hieu river is low about 20.3mg/L where threshold of acceptable aesthetic criteria for human drinking water is 500 mg/l [9] and Most aquatic ecosystems involving mixed fish fauna can tolerate TDS levels of 1000 mg/l [10] After flow into Chau Hanh commune, DO increased from 19.1 mg/L to 21.2 mg/L 6.2.4 Total suspended solids (TSS) Measured values of TSS in study area are shown in the following graph: TSS (mg/L) Total Suspended solids 1000 900 800 700 600 500 400 300 200 100 779 713 831 755 731 805 874 860 895 765 740 723 10 11 12 TSS B2 - QCVN Linear (TSS) Sample Figure 6.6 The analytical result of TSS The result show that: Hieu river in study area is seriously polluted by suspended solids Total of suspended solids indicator of Hieu river water in Chau Hanh commune is high 21 and ranging from 713 mg/L to 895 mg/L These values are higher about 7-8 times than the standards of QCVN 08-MT: 2015/BTNMT 6.2.5 BOD5 and COD Measured values of BOD5 and COD in study area are shown in the following graphs: BOD5 45 38.8 40 BOD5 (mg/L) 35 31.1 31.9 33.2 29.2 35.5 34.4 35.1 33.8 34.3 34.7 30.5 30 25 20 BOD5 15 10 B2 - QCVN Linear (BOD5) 10 11 12 Sample Figure 6.7 The analytical result of BOD5 COD 160 143 131 140 COD (mg/L) 120 105 122 112 109 109 110 117 135 121 97 100 COD 80 60 B2 - QCVN 40 Linear (COD) 20 10 11 12 Sample Figure 6.8 The analytical result of COD The result show that: values of BOD5 and COD of Hieu river water in Chau Hanh commune is higher than the standards In which, the values of BOD is higher about 1.2 – 1.5 times than the B2 standards, ranging from 29.2 to 38.8 mg/L The values of COD is higher 22 about – times than the B2 standard, ranging from 97 to 143 mg/L Both values of BOD5 and COD increased after flow into Chau Hanh commune Thus, Hieu river water after flowing into Chau Hanh commune has been changed in the adverse trend Although the pollution levels is not high but this water source only can used for irrigation activities, cannot use as domestic water 6.3 Economic activities of study area in Hieu River Economic activities is the main reason that reduce land cover in the riparian buffer of Hieu river in Chau Hanh commune Figure 6.9 Map of plant cover in study area The map show that: land cover density in the riparian buffer of Hieu river is lower than other area in Chau Hanh commune This could be explain is because of near the water source would be more favorable to the production activities However, losing of vegetation in the either side of the river will result in changes of water quality 23 From the collected documents and interview survey, the economic activities in Chau Hanh commune are: 6.3.1 Agriculture and forestry - Farming: Farmland accounted for most of the riparian area of Hieu river in Chau Hanh commune By interviewing some local people who lives near the Hieu river, their knowledge about the environment is still limited The main cultivation method of people who lives here is shifting cultivation In the period selected arable land near the forest, they go to the forest to slash and burn forest for plantation crops (rice, cassava, maize ) Forest clearing affecting soil erosion and reduce forest cover Post-harvest phase: people burning after harvest to give the soil nutrients more natural, making the development of microorganisms and faster land reclamation Agricultural can impact on water quality through the release of nutrients (as a result of soil management) and other chemicals (e.g pesticides) into the water environment through biological contamination (e.g from microbiological organisms in manure) and via soil being eroded and washed off farmland [11] - Livestock: By interviewing people in Chau Hanh commune who lives near the the Hieu river, most of their families has cattle, number of cattle from to 10 Their main feeding method is graze freely Cattles are often graze along the riverbank, this livestock method create bad effect to the system of vegetation in riparian buffer of Hieu river 6.3.2 Industry Chau Hanh commune currently not have industrial zone, only some forest product processing facilities However, mining activities on both sides of Hieu river has been happening disorderly and create huge impacts to the Hieu river water pollution Besides cutting down forests for farmland, the mining activities can be said is one of the main causes 24 of TSS pollution in Hieu river in Chau Hanh commune In addition, mining activities can make changes in soil structure and lead to landslides and erosion of the river bank 6.3.3 Trade and services Trade and services in Chau Hanh commune still remain on small scale The investments for development are still not integrated Healthcare and transportation are the main service sectors in Chau Hanh commune and currently not cause much impact on the environment However, these services and business activities are still not much attention to collection and treatment of waste and in the long term will create significant impacts to environment Pictures about research area Sand mining activity in Hieu River (Source: Internet) Gold mining activity in Hieu River (Source: Internet) Roads near Hieu river (Source: field survey) Soil erosion in Hieu river bank (Source: field survey) 25 Nature forest in Hieu river (Source: field survey) Swidden land in Hieu river (Source: field survey) Farmland in Hieu river (Source: field survey) Cattle in Hieu river (Source: field survey) 6.4.Efects of land use on water quality During sampling process, the characteristics of land use in the riparian buffer near each sampling location has been recorded Recorded results are presented in the following table: 26 Table 6.3 Characteristics of sample location Coordinates Sample Latitude Sampling location Longitude 19°33'20.63"N 105° 3'29.15"E Forest land (plantation forest) 19°33'56.57"N 105° 3'52.91"E Farmland 19°33'39.51"N 105° 4'13.71"E Forest land (plantation forest) 19°33'22.87"N 105° 4'45.41"E Farmland 19°33'25.56"N 105° 5'16.01"E Forest land (nature forest) 19°33'36.30"N 105° 5'37.94"E Farmland 19°33'11.03"N 105° 5'52.71"E Road 19°33'13.86"N 105° 6'25.87"E Forest land (plantation forest) 19°33'29.35"N 105° 7'2.80"E Farmland 10 19°33'54.33"N 105° 6'59.43"E Road 11 19°33'36.91"N 105° 7'18.48"E Farmland 12 19°33'33.71"N 105° 7'53.38"E Forest land (plantation forest) The results show that: in the total of 12 sampling locations, locations near the forest land, locations near the farmland and locations near roads Compare with analysis indicator in table 6.1.2, we have table below: Table 6.4 Analysis of water indicators and sampling locations Average values Sampling No Sample DO TDS TSS BOD5 COD (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) location Forest land 1;3;5;8;12 5.5 19.86 766.8 32.6 111.2 Farm land 2;4;6;9;11 5.3 20.6 799.6 33.9 120.6 Roads 7;10 4.9 20.85 819.5 34.9 126.0 Comparison results of each indicators show that: 27 - DO: the average value of DO in samples which near forest land is highest and smallest in the samples which near roads - TDS, TSS, BOD5 and COD in sample which near roads are highest and smallest in the sample which near forest lands 900 800 700 mg/L 600 500 400 300 200 100 DO (mg/L) TDS (mg/L) TSS (mg/L) BOD5 (mg/L) COD (mg/L) Forest land 5.5 19.86 766.8 32.6 111.2 Farm land 5.3 20.6 799.6 33.9 120.6 Roads 4.9 20.85 819.5 34.9 126 Axis Title Forest land Farm land Roads Figure 6.10 Analytical results of water indicators and sampling locations Comparison result of water quality in different types of land use show that: - The quality of water samples which collected near agriculture land and roads are lower than the quality of water sample which collected near forest land This may be explained by the land cover in forest land is higher than agriculture land At the time of sampling, Nghe An province has suffered a heavy rain Therefore, Loss of forest cover, resulting from other land uses such as farmland and roads make increases human-accelerated erosion and leading to decrease water quality of Hieu River In addition, agriculture may affect water quality directly from soil, nutrients and pesticides being transferred from fields to watercourses during rainfall events - The quality of water samples which collected near roads is lowest because of besides the low plant cover density, the dust and waste from vehicles directly impact on the quality of river water 28 6.5 Solutions to improve water quality and sustainable water use in the study area 6.5.1 Policy solution To improve water quality and sustainable water use in Chau Hanh commune, the thesis propose that commune authorities need to promulgate the following policies: - Stricty forbidden all illegal mining activities on Hieu river - Forest protection policy, especially riparian forest - Policies to encourage economic development in forestry, sustainable farming on slopes 6.5.2 Solutions on land use and land planning The decrease of forest resource is one of the main causes that leading to changes in water quality and depletion of water resources in Hieu river According to the survey results, the current remaining forest area in the riparian buffer of Hieu river is very small Therefore, the thesis focus on propose reforestation solution, such as: regeneration and protection of existing forests, nurturing and enrichment of forests, new planting and regenerate forest areas on the riparian buffer - Regeneration and protection of existing forests: is the solution that use natural regeneration for reforestation In areas with favorable conditions, forest regenerated and protected by: prohibition of grazing in regeneration areas to protect the regenerated plants; protect the forest and forbidden to cut tree in protected areas In fact, this work really effectively when assigned management responsibility for the local people, but need to be checked regularly Implement measures for fire prevention and firefighting Shifting cultivation habits of local people still occurs and leading to a high risk of forest Therefore need to implement a policy of prohibiting the burning forest, combined with propaganda, educate local about the important of forest This is an in expensive solution but create high ecological benefit 29 - Nurturing and enrichment of forests: the objects is to nurture and enrich is the woody plants which have ability to cover and improve land quality, plant native trees and strong ability to regenerate such as: Melia azedarach; Acacia auriculiformis; Cinamomum cassia… - New planting and regenerate forest areas on the riparian buffer: application objects is the bare hills, bare land where plants are destroyed by forest fire In the areas of farmland, tree should be planted into the riparian trips to reduce the erosion, encourage people to restricted use of plant protection products… 6.5.3 Technical solution - Environmental Monitoring Solutions: Regularly monitored and evaluate water quality in study area The system of environmental monitoring of surface water quality is set to assess the impact of human activities on water quality and the ability to use water according to different purposes - Application of new technologies in the field of drinking water treatment and processing, wastewater treatment of production before being discharged into the river - Build a database of environmental monitoring by applying GIS and modeling to forecast the changing in water quality of the whole Hieu river basin 30 CONCLUSION Follow the results of the thesis: average flow discharge of Hieu river tended to decrease Water quality of Hieu river in Chau Hanh commune is not satisfied The indicators of TSS, BOD and COD are exceed standard B2 - QCVN Hieu River water is cannot used for the purpose of domestic water, only can used for irrigation purpose Studying the impacts of economic activities to the water quality of Hieu river in Chau Hanh commune indicated that economic activities and characteristics of land use especially in the riparian buffer was generally related to the water quality The build-up land (roads), farmland and forest land has significant influence on water quality and make it change in the adverse direction The result show that the increase of plant cover can contribute to the improvement of water quality The thesis proposed some group of solutions to improve water quality and sustainable use in the study area such as: group of policy solutions; group of land use and land planning solution; technical solution In which the most optimal solution to improving water quality of Hieu river in Chau Hanh commune in the long term is increases forest area The results of this study can provide scientific reference for the local land use optimization and water pollution control and assist the formulation of policies for coordinating the water resource exploitation and protection, especially for rural and mountainous areas in Vietnam This study focus on impacts of economic activities on water quality However, there are many factors related to water quality, such as the climate, precipitation, and density of population 31 REFERENCES [1] http://www.charitywater.org/ [2] I Calder, T Hofer, S Vermont and P Warren Towards a new understanding of forests and water [3] Nguyen Thanh Hang, Ministry of Agriculture and Rural Development Irrigation Planning Institute – Hanoi 1996 Irrigation and water supply planning of the Hieu River in Nghe An province [4] Report in environment situation of Nghe An province in years (2005 – 2009) [5] http://water.usgs.gov/ [6] NOAA Office for Coastal Management How to Use Land Cover Data as an Indicator of Water Quality: Description of Data and Derivatives Used [7] Current status of the integrated management of water resources in Vietnam – Vietnam national environmental report, 2012 [8] Environment report of Vietnam, 2006 – The current state of water environment in river basins of Cau, Nhue – Day and Dong Nai river system [9] WHO/SDE/WSH/03.04/16, Total dissolved solids in Drinking-water [10] American Journal of Environmental Sciences (1): 1-6, 2007 - Effects of Total Dissolved Solids on Aquatic Organisms: A Review of Literature and Recommendation for Salmonid Species [11] The UK water partnership Agriculture’s impacts on water quality – Farming and water [12] Chapter - Forest and water quality - Food and Agriculture Organization of the United Nations (FAO) [13] TCVN 6663-1:2011 (ISO 5667-2: 2006) – Water quality- Sampling Part 1: sampling guides and techniques 32 [14] TCVN 6663-3:2008 (ISO 5667-3:2003) – Water quality- Sampling Guidelines of sample preserving and processing [15] TCVN 6663-6:2008 (ISO 5667-6:2005) – Water quality - Sampling Sampling guidelines on rivers and streams [16] QCVN 08-MT: 2015 / BTNMT national technical regulations on surface water quality 33