Water Quality Assessment Of Santa Cruz River 2011 Prepared and Written By: Darlene T. Tingal – Biologist I Gregory Alexis A. Ongjoco – Chemist II Bileynnie P. Encarnacion – Biologist II Reviewed By: Ms. Adelina C. Santos-Borja, OIC, Resource Mgt. and Development Department Engr. Jocelyn G. Sta Ana, OIC, Environmental Laboratory and Research Division For more information, please contact: Environmental Laboratory and Research Division Resource Management and Development Department Laguna Lake Development Authority Tel. No. 2866143 TABLE OF CONTENTS Page Introduction 1 Objectives 2 Methodology 2 Sampling Stations and Frequency of Sampling 3 Sample Collection, Preservation and Analysis 4 Field Observation and In-situ Measurements 4 Results and Discussion 4 Physico-Chemical Parameters 4 pH 4-5 Dissolved Oxygen 6 Biological Oxygen Demand 7 Nutrient Load 8 Nitrate 8 Inorganic Phosphate 8 Ammonia 9-10 Total Suspended Solids, Total Dissolved Solids and Total Solids 10-12 Turbidity 12-13 Other Parameters 13 Chloride 13 Conductivity 14 Oil and Grease 14 Alkalinity 15 Biological Parameters 15 Phytoplankton 16 Benthos 16-17 Microbiological Analyses 17-18 Conclusion 18-19 Recommendation 19-20 References 21 List of Tables Page Table 1 Stations Coordinates of Santa Cruz River 2 Table 2a.1 General Observation and Description of Sampling Station 1 to 5 (May) 23 Table 2a.2 General Observation and Description of Sampling Station 6 to 10 (May) 24 Table 2a.3 General Observation and Description of Sampling Station 11 to 1 5 (May) 25 Table 2b.1 General Observation and Description of Sampling Station 1 to 5 (Nov) 26 Table 2b.2 General Observation and Description of Sampling Station 6 to 10 (Nov) 27 Table 2b.3 General Observation and Description of Sampling Station 11 to 15 (Nov) 28 Table 3a Physico-Chemical Parameters of Santa Cruz River (May) 29 Table 3b Physico-Chemical Parameters of Santa Cruz River (Nov) 30 Table 3c Computed Unionized Ammonia per Station (May & Nov) 10 Table 4a Water Quality Assessment Based on Algal Population (May) 31 Table 4b Water Quality Assessment Based on Algal Population (Nov) 32 Table 5a Water Quality Assessment Based on Benthic Macroinvertebrates (May) 33 Table 5b Water Quality Assessment Based on Benthic Macroinvertebrates (Nov) 34 Table 6 Results of Microbiological Analysis (May & November) 35 List of Figures Page Figure 1 Map of Santa Cruz River and its Sampling Stations 3 Figure 2 pH 6 Figure 3 Dissolved Oxygen 7 Figure 4 BOD5 7 Figure 5 Nitrate 8 Figure 6 Inorganic Phosphate 9 Figure 7 Ammonia 10 Figure 8 Total Suspended Solids 11 Figure 9 Total Dissolved Solids 12 Figure 10 Total Solids 12 Figure 11 Turbidity 13 Figure 12 Chloride 13 Figure 13 Conductivity 14 Figure 14 Oil and Grease 15 Figure 15 Alkalinity 15 Figure 16 Pictures of Santa Cruz River Stations (May & November Sampling) 36-40 Water Quality Assessment of Santa Cruz River Water Quality Assessment of Santa Cruz River Introduction Santa Cruz is an urban class municipality and the capital town of the province of Laguna. It is situated at the central portion of the Laguna province along the southeastern coast of Laguna de Bay. It is also the seat of the provincial government since 1885, giving the municipality an additional administrative function on the entire province. It lies approximately 87 km southeast of Metro Manila via Calamba and 105 km via Pililla, in the province of Rizal and is geographically located at 14o 17’ latitude and 121o25’ longitude. It is accessible by land from the nearby 28 municipalities and by water through Laguna de Bay from Manila and some Rizal towns. The municipality is bounded by Laguna de Bay on the north, by Lumban and Pagsanjan towns in the east, Pagsanjan and Magdalena towns in the south, and Pila and Liliw towns in the west. Santa Cruz town is situated on the banks of the Santa Cruz River and course its way along the eastern part of the famous Laguna de Bay. Santa Cruz is considered as the service and commercial center on the eastern part of Laguna province. The town is composed of 5 barangays in the Poblacion area and 21 classified urban barangays. Santa Cruz River is one of the 21 major tributary rivers of Laguna de Bay contributing about 15% of the total water in the lake. During the typhoon “Milenyo”, the Calumpang Diversion Dam was destroyed due to overflowing of the river. Built in 1970, the dam channeled irrigation canals around the Calumpang area. The water is used as a source of irrigation for 2185 hectares ricefields in Pila, Santa Cruz, Liliw, Victoria and Nagcarlan. The riverbed is characterized by rocks, pebbles to sandy bottom where quarrying along the river was also one source of income aside from fishing. According to the National Irrigation Authority, quarrying could be the cause of erosion and deepening of riverbed to 12 m lower than the old depth. The width and length of the river could be comparable to Pagsanjan River. However, the volume and capacity of Santa Cruz River were exceeded during the tropical cyclone “Santi” (2009). Santa Cruz River submerged 85% of the town, 6 ft at Brgy. San Pablo Norte, waist-deep at Brgy. Santisima Cruz and San Pablo Sur while leg-deep at Brgy. Inang Awa. According to Water Usage and Classification for Freshwater System used by DENR Santa Cruz River was classified as Class D, which is suitable for agricultural irrigation, livestock watering and industrial water supply (WQ Status Report, 2005). However, in 2001-2005, one of the river tributaries that passed the Class C dissolved oxygen criterion was Santa Cruz River (EMB 2006). The river runs through municipalities and considered as fishing ground to small fish farmers along the area. Fishes caught in the river are tilapia, dalag, shrimp, kanduli and other fishes including invasive species like knifefish and janitor fish. Laguna Lake Development Authority – Environmental Laboratory and Research Division Water Quality Assessment of Santa Cruz River 2 Objectives In 1996 LLDA launched its River Rehabilitation Program utilizing an integrated approach on the management of the watershed, taking into account the water quality and other activities that thrives along the river system all the way to Laguna de Bay. As part of the River Rehabilitation Program of Resource Management and Development Department (RMDD), the assessment of the water quality of Santa Cruz was undertaken for the dry and wet season for the purpose of determining seasonal variations of the water quality in terms of biological, chemical and bacteriological parameters. Water quality was assessed based on the biological organisms characterized as clean to polluted indicators and the physico-chemical parameters. Other observations in relation to development and activities within the river system and its watershed were taken into account. The study serves as baseline information on the use and activity of the Santa Cruz River and its watershed. Methodology Sampling Stations and Frequency of Sampling Fifteen (15) sampling stations at various sections of the river and its tributaries were already established since 1998. Reconnaissance of the established stations was again done to determine if changes in the original stations need to be made. Sampling stations were selected strategically along the Santa Cruz River and its tributaries and coordinates of each station were established using the Global Positioning System (GPS) presented in Table 1. Stations established along the stretch of the river and representative section of its tributaries are shown in Fig. 1. The frequency of sampling was represented by two seasons. The May (May 17 and 18, 2011) represent the wet season while November (November 24 and 28, 2011) represent the dry season. Table 1. Stations Coordinates of Santa Cruz River Station Location Coordinates 1 Mouth (Santa Cruz) P 0327797 1580793 2 Brgy. Santo Angel P 0328548 1579893 3 Brgy. Pagsawitan P 0329736 1577880 4 Brgy. Calumpang P 0328151 1568855 5 Brgy. Sta. Lucia P 0328152 1568680 6 Brgy. Bancoro P 0328464 1567064 7 Brgy. Palina P 0329238 1563630 8 Brgy. Balinacon P 0329270 1563038 9 Brgy. San Francisco P 0329720 1560074 10 Brgy. Pook P 0327773 1560676 11 Brgy. Laguan P 0326441 1561843 12 Brgy. Panglan P 0332779 1563381 13 Brgy. Ibabang San Roque P 0332430 1563198 14 Brgy. Palayan P 0327511 1563348 15 Brgy. Cabuyew P 0328852 1566677 Laguna Lake Development Authority – Environmental Laboratory and Research Division Water Quality Assessment of Santa Cruz River 3 Fig. 1. Map of Sampling Stations of Santa Cruz River Laguna Lake Development Authority – Environmental Laboratory and Research Division Water Quality Assessment of Santa Cruz River 4 Sample Collection, Preservations and Analysis Water samples were collected in each station by grab method and with the use of plastic pail in stations with depth more than 1 foot. The water samples for chemical analysis were placed in the designated container with label and preserved in the cooler with ice. Microbiological samples were collected by grab method using the sterilized bottles and preserved with ice in a separate cooler. Samplers used for the collection of biological samples were surber sampler and ekman dredge. Benthic flora and fauna were collected using surber sampler for water depth below 1 foot while ekman dredge for water depth 1 foot and above. Sediment samples collected using ekman dredge were processed by allowing the collected sediment to pass through a sieve with mesh size of 180 m. The samples left in the sieve was transferred to a screw cap plastic container of 100 and 250 ml capacity for flora and fauna analysis, respectively. Samples for benthic flora were preserved with 3 to 5 drops of Lugol’s solution while benthic fauna with 2 ml of formalin. Samples for biological samples were stored under room temperature prior to analysis.