Land Use and Water Quality in El Corpus, Choluteca, Honduras
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LAND USE AND WATER QUALITY IN EL CORPUS, CHOLUTECA, HONDURAS By OLAF ZERBOCK submitted in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE IN FORESTRY MICHIGAN TECHNOLOGICAL UNIVERSITY 2005 The research report: “Land Use and Water Quality in El Corpus, Choluteca, Honduras” is hereby approved in partial fulfillment of the requirements for the Degree of MASTER OF SCIENCE IN FORESTRY. School of Forest Resources and Environmental Science Signatures: Advisor:_____________________________________ Blair Orr Dean:______________________________________ Margaret Gale Date:______________________________________ ii TABLE OF CONTENTS LIST OF FIGURES…………………………….…………………………… iv LIST OF TABLES………………………………………………………….. vi ACKNOWLEDGEMENTS…………………………………………………… vii ABSTRACT...……………………………………………………………… viii CHAPTER 1 INTRODUCTION…………………………………………… 1 CHAPTER 2 COUNTRY BACKGROUND FOR HONDURAS……………….. 4 CHAPTER 3 STUDY AREA BACKGROUND: SOUTHERN HONDURAS AND EL CORPUS…………………….…………………………. 16 CHAPTER 4 METHODS………………………………………………… 36 CHAPTER 5 DATA…………………………………………………….. 51 CHAPTER 6 RESULTS AND DISCUSSION……………………………….. 65 CHAPTER 7 CONCLUSION AND RECOMMENDATIONS………………….. 94 LITERATURE CITED………………………………………………………. 102 APPENDIX 1 FIELD DATA………………………………………………... 108 APPENDIX 2 LABORATORY RESULTS………………………………......... 139 APPENDIX 3 DEFOMIN REPORTS………………………………………. 141 iii LIST OF FIGURES FIGURE 1. MAP OF HONDURAS.........................................................................................................................5 FIGURE 2. NEIGHBORHOOD ON A PRECARIOUS HILLSIDE IN TEGUCIGALPA...…............................................... 7 FIGURE 3. TIMBER EXTRACTION IN PINE FOREST BY RELATIVELY SMALL-SCALE OPERATORS. .......................12 FIGURE 4. CLEARED LAND FOR HILLSIDE AGRICULTURE AND GRAZING INSIDE THE RÍO PLÁTANO ................13 FIGURE 5. MAP OF SOUTHERN HONDURAS AND THE MUNICIPIO OF EL CORPUS .............................................16 FIGURE 6. LOOKING EAST FROM EL CORPUS ACROSS THE CHOLUTECA VALLEY............................................17 FIGURE 7. THE TOWN OF EL CORPUS..............................................................................................................19 FIGURE 8. MONTHLY MEAN PRECIPITATION (1978-1988) AND POTENTIAL EVAPOTRANSPIRATION............... 24 FIGURE 9. THE APTLY-NAMED CEDRO ESPINO (BOMBACOPSIS QUINATA)........................................................27 FIGURE 10. EVERGREEN AND DECIDUOUS TREES IN MID-MARCH..................................................................28 FIGURE 11. DRY SEASON MOSAIC OF POST-HARVEST CROP FIELDS, FALLOW LANDS AND PASTURES..............30 FIGURE 12. NEWLY PLANTED CROPS ON ERODED AND GULLIED HILLSIDE AND STEEPLY SLOPING BURNED PASTURES ADJACENT TO THE TOWN OF EL CORPUS. .............................................................................33 FIGURE 13. LIVE GRASS BARRIERS INSTALLED TO REDUCE EROSION ON STEEP SLOPES IN THE GUANACAURE MULTIPLE USE AREA .............................................................................................................................34 FIGURE 14. THE RÍO CALDERAS WHERE IT ENTERS THE CHOLUTECA VALLEY. ..............................................36 FIGURE 15. LOCATIONS OF SAMPLE POINTS ALONG THE SAN JUAN AND EL SABROSO WATERSHEDS. ............39 FIGURE 16. SITE JD, ON THE QUEBRADA SAN JUAN, IN EARLY NOVEMBER. ..................................................40 FIGURE 17. STREAMSIDE EROSION AND LOW FLOW CONDITIONS NEAR POINT SB ON THE QUEBRADA EL SABROSO. .............................................................................................................................................42 FIGURE 18. THE OAKTON T-100 CONDUCTIVITY METER................................................................................48 FIGURE 19. PH VALUES OBTAINED ON EIGHT OCCASIONS AT SITE JA ON QUEBRADA SAN JUAN.....................52 FIGURE 20. CONDUCTIVITY MEASUREMENTS OBTAINED ON ELEVEN OCCASIONS AT SITE SC ON QUEBRADA EL SABROSO.........................................................................................................................................53 FIGURE 21. FLOW AND CONDUCTIVITY VALUES BY SAMPLE SITE ACROSS ALL SAMPLING EVENTS.................55 FIGURE 22. TURBIDITY MEASUREMENTS TAKEN ON EIGHT OCCASIONS AT SITE CC........................................56 iv FIGURE 23. FLOW AND TURBIDITY VALUES BY SAMPLE SITES ........................................................................57 FIGURE 24. RIVER FLOW MEASURED AT THREE SAMPLING SITES....................................................................58 FIGURE 25. DAILY PRECIPITATION MEASURED AT EL CORPUS FROM 10-19-04 TO 8-03-05............................59 FIGURE 26. DAILY PRECIPITATION MEASURED AT AGUA FRÍA FROM 10-19-04 TO 8-03-05............................59 FIGURE 27. LAND USE CLASSES......................................................................................................................63 FIGURE 28. LAND USE IN THE Q. SAN JUAN AND Q. EL SABROSO WATERSHEDS. ...........................................64 FIGURE 29. UPPER RÍO CALDERAS DURING THE DRY SEASON. ALTHOUGH A TRICKLE OF WATER IS ..............67 FIGURE 30. CUMULATIVE RAINFALL FOR PAST SEVEN DAYS ..........................................................................68 FIGURE 31. WATER FLOW AND TURBIDITY AT THREE SAMPLE SITES ..............................................................71 FIGURE 32. WATER QUALITY MEASUREMENTS FOR SAMPLE SITES JB AND JC. ...............................................75 FIGURE 33. CONDUCTIVITY VALUES RECORDED AT FOUR SITES ON THE QUEBRADA SAN JUAN.....................76 FIGURE 34. WATER QUALITY MEASUREMENTS FOR SAMPLE SITES JB AND JC ................................................79 FIGURE 35. WATER QUALITY MEASUREMENTS FOR SAMPLE SITES JA, SA AND CC..........................................82 FIGURE 36. CONDUCTIVITY VALUES FOR THREE SAMPLE SITES......................................................................83 FIGURE 37. RUNOFF FROM THE GOLD MINE PROPERTY DRAINS INTO THE Q. EL SABROSO .............................86 FIGURE 38. WATER QUALITY MEASUREMENTS FOR SAMPLE SITES SB AND SC................................................87 FIGURE 39. CONDUCTIVITY VALUES FOR TWO Q. EL SABROSO SAMPLE SITES ...............................................88 FIGURE 40. PH MEASUREMENTS AT TWO SITES ON Q. EL SABROSO ...............................................................89 FIGURE 41. TURBIDITY VALUES FOR TWO SAMPLE SITES ON THE Q. EL SABROSO..........................................90 v LIST OF TABLES TABLE 1. POPULATION, DENSITY AND GROWTH IN EL CORPUS, CHOLUTECA.................................................22 TABLE 2. COMPARISON OF CONDUCTIVITY AND TURBIDITY VALUES OBTAINED BY LABORATORY VS FIELD MEASUREMENTS. ..................................................................................................................................61 TABLE 3. LAND USE IN THE Q. EL SABROSO AND Q. SAN JUAN WATERSHEDS ...............................................62 vi ACKNOWLEDGEMENTS Whether or not the journey is the destination, no journey is undertaken alone. Along the way, one’s experiences are shaped by countless individuals. From the first day to the last, I have been fortunate to meet many that reaffirmed the value of what was a fantastic experience. I could never list you all, but hopefully many of you know who you are. At Michigan Tech, I would like to acknowledge the unwavering support of my advisor, Blair Orr. His commitment to his students and the Peace Corps program at Michigan Tech continues to benefit all involved, including those in developing countries around the world who will never know him. For their time and interest in my studies I would like to thank my graduate committee, Andrew Storer, Hugh Gorman, Dana Richter and especially Alex Mayer, who invested time and insight into this project before even having met me. Thanks also to Ann Maclean for her time and assistance with GIS image processing. In Honduras, I would like to thank the Peace Corps/Honduras staff, especially Luis Estrada and Menelio Bardales, for their commitment to their volunteers and their dedication to helping Honduran citizens live healthier and more fulfilling lives. Thanks also to Maritza Montoya, at Aguas de Choluteca, for her interest in my project and assistance with processing water samples delivered by an (occasionally) impatient and (usually) dirty gringo. Mr. Peter Hearne of USAID-Honduras was also very helpful in providing background material. I would like to thank all the dedicated professionals in Honduras with whom I had the opportunity to work and learn. A mis amigos y familia en El Corpus, les quiero agradecer por cada día que compartieron conmigo. Les quiero mucho. Gracias por todo. Finally, I would like to thank my parents for their support in every turn my life takes. It’s a long road, but your unconditional encouragement makes it all worth it. Cheque pues… vii ABSTRACT The intent of this study is to examine the current condition of the Rio Calderas watershed in southern Honduras. High rural population densities, intensive land use for traditional annual crops, the expansion of cattle pasture as an economic alternative and precious metal mining all threaten the quality of surface water in the area. A very pronounced dry season places further stress on water supplies for up to five months of the year. Land use was classified in two subwatersheds, the Quebrada San Juan and the Quebrada El Sabroso. Agriculture,