Field Survey and Satellite Validation of Water Quality Parameters of Rivers in the Surroundings of Santo Domingo Metropolitan Area, Dominican Republic

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1 EMECS 9 (Baltimore, August 2011) Field Survey and Satellite Validation of Water Quality Parameters of Rivers in the Surroundings of Santo Domingo Metropolitan Area, Dominican Republic Hiroshima University E. R. Miño A., Y. Sakuno, T. Okuda, H. Mutsuda, S. Nakai, W. Nishijima Santo Domingo Autonomous University (UASD) M. Rodriguez and F. Reyes Municipality of Santo Domingo East, DR R. Castro

2 Background USA Cuba Haiti Dominican Republic Haina River H3 H1 H2 O1 Ozama River I1 O2 I2 Isabela River O3 Ozama River Dominican Republic Haina River Ozama River H8 H9 H7 H5 H6 H10 H4 O4 O5 O6 O7 O8 O9 Caribbean Sea O10 O11 The Caribbean Sea, known as one of the world s leading tourist destinations, is surrounded by many islands and facing pollution by rivers. Little concern has been paid to pollutant loadings by the rivers due to lack of resources. In this study, we focused on satellite remote sensing technique as an affordable monitoring method to estimate the loadings. The studied rivers flow in the surroundings of Santo Domingo, the capital of the Dominican Republic.

3 About 1/3 of the population of Dominican Republic is concentrated in the Santo Domingo Metropolitan Area (SDMA). Ozama-Isabela and Haina Rivers are the three main rivers in the surroundings of SDMA. One of the main problems in SDMA seems to be the pollution of these rivers caused by the discharge to the rivers and ravines of untreated sewage and industrial wastewater. Another problem is also the discharge of garbage to the rivers front as well to the ravines and rivers. Ozama-Isabela and Haina Rivers discharge to the Caribean Sea, therefore the loadings may have a great influence to the environment and cause the coastal area production.

4 Problems of satellite water color remote sensing technique Ocean color sensor Chl-a map (4km resolution) Satellite remote sensing is now accepted as an important monitoring technique in the world s oceans. (SeaWiFS, MODIS, etc.) D.R. Problems of satellite use in coastal environments (1)The spatial resolution of these satellites is greater than 1 km. (2)It is difficult to estimate chlorophyll-a because of co-existing SS Coastal area Satellite Chl-a vs in-situ Chl-a (1)Utilization of the land sensor (e.g. LANDSAT, ALOS) (2)Local robust algorithm development (Need: spectral reflectance data)

5 Objectives Perform field surveys of the water quality in Ozama-Isabela and Haina Rivers, and the nearby Coastal area. Validate the data using satellite imagery.

6 Overview of Surveyed Area from Satellite Isabela River Santo Domingo City Osama River Haina River Caribbean Sea Satellite image : ALOS/AVNIR-2, Observation Date:2010/11/19

7 Sampling Points O-10 O-9 O-8 O-11 O-12 H-1 H-2 H-3 O-14 O-13 H-9 H-6 H-5 H-6 H-4 O-15 O-7 H-7 H-8 O-3 O-4 O-2 O-1 O-6 O-5

8 Caribbean sea

9 Sampling Points O-10 O-9 O-8 O-11 O-12 H-1 H-2 H-3 O-14 O-13 H-9 H-6 H-5 H-6 H-4 O-15 O-7 Floating bridge H-7 H-8 O-3 O-4 O-2 O-1 O-6 O-5

10 S alinity (P S U ) S alinity (P S U ) Salinity Before Floating Bridge J an M arch After Floating Bridge Ravine discharge 5 0 Haina River D istance from the m outh Ozama-Isabela Rivers J an M arch D istance from the m outh

11 Floating bridge before Ozama river mouth

12 T urbidity (N T U ) T urbidity (N T U ) Turbidity Sewage discharge Ravine discharge D istance from the m outh Ozama-Isabela Rivers J an M arch Haina River Garbage dumping sites D istance from the m outh J an M arch

13 Ravine into Isabela River DO 0.29 mg/l

14 Slum

15 Dumping of solid waste

16 Sewage pipe from an avocado processing plant

17 Garbage dumping

18 C H L -a (ug/l) C hl-a (ug/l) Chlorophyll-a Sewage discharge Ravine discharge J an M arch D istance from the m outh Ozama and Isabela Rivers Port Haina River Garbage dumping sites J an M arch D istance from the m outh

19 Sampling Points O-10 O-9 O-8 O-11 O-12 H-1 H-2 H-3 O-14 O-13 H-9 H-6 H-5 H-6 H-4 O-15 O-7 H-7 H-8 PORT O-3 O-4 O-2 O-1 O-6 O-5

20 D O (m g/l) D O (m g/l) Dissolved Oxygen Sewage discharge J an M arch 8 6 Ravine discharge D istance from the m outh Ozama and Isabela Rivers Haina River Garbage Dumping sites J an M arch D istance from the m outh

21 SS and Chl-a Distributions Ozama-Isabela Rivers (March)

22 Haina SS Color Analysis O-3 O-4 Ozama - Isabela O-6 O-8

23 Correlation between turbidity and ALOS bands

24 Example of correlation analysis between satellite data and in-situ data (Osama-Isabela) Satellite Reflectance data In-situ data St B1 B2 B3 B4 Chl-a SS Turb /11/ /1/30 The satellite and the simultaneous water quality data acquisition are necessary to validate the water quality estimation algorithm true.

25 SS (mg/l) Chl-a ( g/l) Correlation between satellite and in-situ data Correlation coefficient (r) B1 B2 B3 B4 B1/B2 B1/B3 B1/B4 B2/B3 B2/B4 B3/B4 N SS Chl-a B: Band, Exception of Chl-a=0 condition 30 SS 40 Chl-a y = x R= y = x R= ALOS DN[Band1/Band4] ALOS DN[Band2/Band3]

26 Mapping SS and Chl-a distributions Isabela River Isabela River Osama River Osama River Haina River Haina River Mask Mask SS (mg/l) Chl-a (μg/l) If many new satellite/in-situ data sets are obtained, a robust water quality estimation algorithm by satellite in this region will be constructed. It is necessary to strenghten the observation environment to obtaining such data set. (e.g. Buoy[tower] or in-situ SS or Chl-a constantly monitoring system)

27 River Influence

28 Detail WorldView-2 image of Jun 7 th, 2011 Isabela River Santo Domingo Ozama River Ozama River Santo Domingo High turbidity Caribbean Sea

29 Satellite Image (June 2011) SS map Chl-a map mg/l 0 20 ug/l SS: World View-2 Band4/Band1(608nm/427nm) Chl-a: World View-2 Band6/Band5(724nm/608nm)

30 Conclusions A significant correlation was observed between the color spectra of water and ALOS bands, which shows the possibility of the use of remote sensing to determine the macro situation of pollution in the rivers and coastal areas. SS, turbidity and chlorophyll-a values are very high while DO levels are very low in places near ravine discharge, sewage pipe ends and garbage dump sites. Both rivers present hyper-eutrophic characteristics, especially in areas near ravine and sewage discharges. The hyper-eutrophicated rivers may be inducing a high load of nutrients to the coastal area. Remote sensing could be a tool to estimate loadings from rivers.

31 THANK YOU

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