y'^ '£ji 'M AN INTEGRATED NATURAL RESOURCES EVALUATION PH F *V' •\"^il ^-'tEßh, :«i3" t1 ^%'jr1 £<T3<:- > r-i SURVEY FOR THE DEVELOPMENT OF THE GUAYAS RIVER DASIN OF ECUADOR Scanned from original by ISRIC - World Soil Information, as ICSU World Data Centre for Soils. The purpose is to make a safe depository for endangered documents and to make the accrued information available for consultation, following Fair Use Guidelines. Every effort is taken to respect Copyright of the materials within the archives where the identification of the Copyright holder is clear and, where feasible, to contact the originators. For questions please contact soil.isric(5)wur,nl indicating the item reference number concerned. An Integrated Natural Resource Evaluation Prepared in the Department of Economic Affairs of the PAN AMERICAN UNION General Secretariat, Organization of American States WASHINGTON, D.C. 1964 3oo3 ERRATA age Line Reads Should Read 18 17 FAO Report No. 728 FAO Report No. 748 38 31 mosture moisture 53 45 ooels are coal deposits are 72 28 predominately predominantly 73 8 Appendix F Appendix G 75 13 later to forest later return to forest 75 ifO 1,000 mm. 4,000 mm. 93 7&13 (NIB) (CNR) 21 7 fiew view ABSTRACT In 1962, a request was made by the Government of Ecuador to the General Secretariat of the Organization of American States for technical assistance in surveying and assessing Ecuador's natural resources, so as to provide an informational base for development planning and programming. The request was responded to by the Natural Resources Unit of the OAS* Department of Economic Affairs. Specifically, the technical assistance took the form of two mis­ sions: (l) an inventory and evaluation of the information basic to resource development, and of the programs and capabilities of Ecuadorian institutions concerned with investigations, mapping and development in this sector, fol­ lowed by (2) an integrated reconnaissance study of the natural resources of the Guayas River Basin on Ecuador's Pacific coast. The findings of both technical assistance missions are included in this report. The National Inventory The national inventory and evaluation sought to determine the infor­ mational needs for national resource development planning and the extent to which Ecuadorian institutions and technical personnel could fill these require­ ments« An inventory was made of available aerial photographs, topographic, geologic, soils, vegetation and land use maps and studies, and the institu­ tional programs and personnel for data collection and mapping were reviewed and evaluated. It was found that there was insufficient data for effectively planning and programming resources development; important types of mapping did not exist and available topical maps and studies were too generalized for the purposes of the development planner. Furthermore, the institutional and technical capabilities were so limited as to preclude rapid data acquisition and analysis on a national scale for planning and programming resource de­ velopment. The substantial time and cost required to obtain the needed information was not judged to be commensurate with the stated desirability of planning and executing development programs in the shortest time possible. In consultation with Ecuadorian authorities, the decision was made to concentrate study efforts on a region within the country with good resource potentials and development possibilities. The Guayas River Basin was selected and the OAS entered into an agreement with the Ecuadorian government to undertake an integrated evaluation of the Basin's natural resources in order to provide a point of departure for planning and programming regional development. 111 Tine Integrated. Evaluation of tine Guayas Kiver Basin. In mi"d-1963, an OAS-supervised technical team consisting of a geographer, a forester, an irrigation engineer, a soils surveyor and a geologist completed a six-month reconnaissance of the climate, geology, geomorphology, water re­ sources and irrigation systems, soils, forests, land use, and population distribution in the Guayas River Basin and its watershed. Data obtained from aerial photographs and field surveys, as well as from existing studies and maps, were compiled and analyzed. Maps of geology, soils, land use and vege­ tation, and population distribution were compiled at a scale of 1:500,000. Smaller scale maps depicting monthly and annual rainfall distribution, eco­ logie formations and geomorphology were also prepared. A synthesis of the re­ lative values of the different physical resources was accomplished by carto­ graphic superimposition. For this purpose an analytic map depicting differing values of terrain conditions and soils, surface water and forest potentials was compiled. This map constituted a base for weighing the importance to development of climate, population distribution, land use and the existing transportation network. A map depicting development regions was then constructed which synthe­ sizes the assessment of development potentials and problems as influenced by the various factors taken into consideration in the analysis. The Guayas River Basin The 33»6i+0 square kilometer watershed of the Guayas River consists of a broad north-south trending basin whose extensive southern flood plain merges with an undulating and partially dissected landscape in the upper river Basin. The Basin is enclosed by the elevated and steep Andean Cordillera to the east, and lower, dissected ranges to the north and west. The very humid tropical climate and erosional processes acting upon the basic igneous and volcanic rocks of the Andean slopes have provided the Guayas plain with approximately 9*500 square kilometers of fertile alluvial soils, whose agricultural capabilities are diminished in varying degrees by seasonal drought, flooding and poor drainage over some 6,000 square kilometers in the dry tropical southern flood plain. The numerous tributary streams with head­ waters in the humid Andean front, however, offer good possibilities for irri­ gation development where they traverse the southern flood plain; also, the deep sediments found here are judged to have abundant groundwater reserves. Principal economic crops of the southern flood plain are sugar cane, bananas, cacao, cotton and rice; castor beans, citrus and other fruits are also culti­ vated. Present irrigation is newly developed and confined to two small areas west of the port city of Guayaquil. Irrigation distribution networks have been found to be incomplete and inadequate, resulting in inefficient water use. Generally speaking, a low level of technology is employed in agricultural IV production throughout the southern flood plain. Rural population is moder­ ately dense, tending to concentrate along the road and water routes leading to Guayaquil. The northern sector of the Guayas Basin has considerable areas of well drained, fertile volcanic soils which receive adequate rainfall and are not subject to seasonal drought. Other soils are less fertile owing to parent material origin and the leaching effects of high rainfall. Evergreen and deciduous broadleaf forests found in this more sparsely populated portion of the upper Guayas Basin occupy an estimated 6,000 square kilometers and have timber volumes ranging from 20,000 to 40,000 board feet per hectare on well drained sites. Among the commercial species found is balsa, which has been heavily exploited in the more accessible zones. Roughly 3*500 square kilo­ meters of forested or partially settled lands between Quevedo and Santo Domingo de los Colorados have excellent soils and very good settlement po­ tential . On the forested tropical hills and dissected ranges of the northwest, continuous timber exploitation is possible, but agricultural development is made less feasible by broken terrain, poor soils and high rainfall. In the general vicinity of Quevedo and Balzar some 2,^00 square kilometers of land are in the process of settlement and agricultural development. Bananas are the principal crop; cacao is grown to a lesser extent. Ecologie conditions favor the cultivation of African oil palm. These lands could absorb perhaps twice as many rural inhabitants through colonization. The lower Andean slopes offer diverse development possibilities: peren­ nial agriculture, forest exploitation, multi-purpose hydroelectric projects and mining. Steep slopes and high rainfall hinder certain phases of develop­ ment and create problems in soil conservation and road construction and main­ tenance. Principal Resource Potentials and Problems to Development The principal natural resources of the Guayas Basin are its fertile soils, abundant ground and surface water and tropical forests. Metallic minerals are of limited occurrence and oil, gas or coal have not been discovered nor do there exist geologic reasons for believing they exist. Future development will therefore be primarily in forest exploitation and agriculture, both irrigated and unirrigated. A major physical problem hindering the development of these resources is the nature of the lowlying, flat terrain to the south which causes poor soils drainage and flooding and creates difficulties with irri­ gation and drainage measures. Along the Andean slopes the feasibility of water impoundment is reduced by steepness of stream gradient and narrowness of canyons. Conversely the lack of gradient and terrain features favorable to water impoundment in the Guayas plain limit possibilities of reservoir con­ struction. In the east central portion of the Guayas