The World Bank Rural Week 1999
Political Dimensions of Sustainable Rural Development
Sustainable Intensification
Task: "Assessing the
environmental and economic impacts of integrated watershed management in Santa Catarina,
Brazil, over the period 1988-1997"
BETTER ENVIRONMENT, BETTER WATER, BETTER INCOME AND BETTER QUALITY OF LIFE IN MICROCATCHMENTS ASSISTED BY THE LAND MANAGEMENT II PROJECT/WORLD BANK
LAURO BASSI CHAPECÓ (SC), MARCH/99
ACKNOWLEDGEMENTS
We wish to thank all the
technicians and entities who enabled us to carry out this study, especially the farmers in
the watersheds, the extensionists, EPAGRI (Agricultural Research and Rural Extension
Company of Santa Catarina), CASAN (Santa Catarina Water and Sanitation Company) and the
World Bank. We also wish to thank Brandeli Maria Merrigo, Viviane Dias Azevedo and Cézar
Luiz Mignoni, for typing and design, and Janice Molina for translation support.
CONTENTS
3.1 - Vegetation Cover of Soil
3.2 - Water Infiltration in Soil
Lauro Bassi
The immediate causes of the process of natural resources degradation, including soil erosion, include improper use and management of lands in microcatchments. Direct consequences, on the one hand, are soil impoverishment and gradual decreases in crop yields, and, on the other hand, reduced water quality and quantity in rivers and microcatchment sources. In economic terms, effects are felt in the reduced income of families who reside in the microcatchments, causing them to abandon and sell their properties, thereby contributing to an increase in social problems in the outskirts of urban areas where many of these families settle. In order to deal with the widespread problems of natural resource degradation, it was necessary to adopt new strategies based on modern soil erosion and conservation concepts, based more on land management than on isolated conservation practices which often do not combat the causes of erosion but rather their effects. The technical strategy must seek to both combat the causes of the problem and bring immediate economic results to the farmers involved. The intervention methodology should be based on participatory planning, which is focused on people rather than things. The aim of the Land Management II Project is to plan land use and management efforts aimed at achieving balance with the environment so as to produce rather than degrade, and to provide worthwhile living conditions for families through sustained increases in income. The aim of this study is to present the results of environmental improvements, particularly for water, obtained through the implementation of Better Management Practices (BMP), in microcatchments monitored by the World Bank’s Land Management II Project. Issues of increased income and the organization of farmers are also presented. The philosophical, strategic, technical and methodological aspects of the World Bank’s Land Management II Project developed in Santa Catarina are similar to those developed in the Paraná Project. Considering that the state of Santa Catarina presents highly specific, complex issues of topography, climate, agrarian structure and activities which comprise the production system (concentration of hogs in small farms), the Project has several differences in strategic and technical focus to allow anticipated results to be achieved.
Considering that natural resource degradation and water pollution occur everywhere (in rural and urban areas), precise intervention needs to be done in a systematic (holistic) manner, albeit concentrated in a natural geographic space (to cause visual impact and solve problems jointly, since prompt actions do not solve generalized problems), allowing planning in the field and on farms. To deal with these principles, the geographical area best suited for intervention is doubtless the microcatchment which, besides being a natural hydrological system, is where live the farmers who directly influence natural resources. The World Bank Land Management II Project in Santa Catarina, in addition to adopting a participatory methodology, implemented a technical strategy based on research results, with the following objectives:
Increase vegetation cover of soil;
Increase water infiltration in soil profile;
Reduce surface runoff;
Reduce water pollution.
Farmer organization and group technical assistance were encouraged as elements of strategic support. To measure the project’s results, indicators dealing with technical strategy objectives were selected together with measuring the degree of farmer organization and income of rural families.
Indicators analyzed:
a) Rainfall
Through the use of pluviographs and pluviometers, installed on farms and in research centers, all rainfall data in monitored microcatchments is followed closely;
b) Vegetation cover and water infiltration in soil profile
The main cause of erosion in Santa Catarina is rain. Although rain is rather uniformly distributed throughout the year, rainier months coincide with the planting of winter (May and June) and summer (October and November) crops. The quantity and intensity of rainfall, the irregular topography and the intense use of land, sometimes for purposes to which it is not suited, which occurs in Santa Catarina, lead us to consider vegetation cover of soil as the most practical management practice to control erosion and ensure greater water infiltration in the soil profile. Vegetation cover is measured by systematically monitoring microcatchment and farm management plans. Water infiltration is indirectly measured by the increase in the area covered and by the performance of levels of rivers and hydrographic peaks, in the control section at the end of the microcatchment.
c) Reduction of surface runoff
Following the impact of rain on unprotected soil surfaces and the dislodging of particles, the process of transporting the dislodged material begins, most of which ends up in the microcatchment’s water network, causing the siltation of rivers, lakes and dams, and influencing water quantity and quality. The amount of sediments transported to rivers is directly related to surface runoff. Thus, by measuring water turbidity and concentration of sediments in suspension, one obtains a clear indicator of the surface runoff and erosion which takes place in the microcatchment. This also serves to gage the efficiency of Better Management Practices implemented in the system. In rivers which supply cities, aluminum sulfate is used for the flocculation and subsequent decantation of solids in suspension. If one knows how much of this element is used to treat water, one has an indicator of erosion in the microcatchment in which water is taken in.
d) Reduction in water pollution
Sediment, with what it carries absorbed, is an agent that reduces water quality. However, considering that the Land Management II Project is being carried out in regions of the state with high livestock concentrations (hogs, poultry and cows) on small farms with shallow, sloping and rocky soils, where it is difficult to properly dispose of waste, understanding organic pollution means understanding the efficiency of basic sanitation and of waste management in the microcatchments assisted. The basic indicator used to measure organic pollution is the concentration of coliform bacteria in microcatchment waters. In addition to these indicators, nutrient loss in the Lajeado São José microcatchment, Chapecó/SC, was measured along with sediments, and, in economic terms, the evolution of family income and the increase in the number of farmers’ groups were closely followed. The data presented is from the following sources:
Monitoring over a ten-year period in the Lajeado São José microcatchment, Chapecó, SC, with data prior and subsequent to project implementation;
Information sought from CASAN (Santa Catarina Water and Sanitation Company), stemming from routine monitoring of raw water used for urban supply.
Project water resource monitoring system;
Reports received from extensionists and researchers involved in the Project.
The use of this methodology, although it may contain
statistical errors, has the advantages of being economical and easily applied and of
providing unique, basic information on monitored microcatchments. It also indicates the
trends of parameters studied, in accordance with the objectives of the water resource
monitoring component. Note, however, that through the use of simple indicators which can
be obtained at water treatment stations, it is possible to prove the effect of
intervention in the microcatchments assisted.
The following are results from microcatchments assisted in different regions of the State of Santa Catarina.
3.1 – Vegetation Cover of Soil
The project’s strongest technical message for eliminating the main cause of erosion, which is the impact of raindrops on bare soil, has been to implement vegetation cover of soil. With the implementation of these guidelines for farmers, it was noted that, before the start-up of the World Bank Land Management II Project, soil cover throughout the year remained at an average of 15%. Today, the microcatchments assisted under the project have a soil cover index of 80%. The major acceptance of soil cover by microcatchment farmers is due to the fact that, under this cover, economic crops are implemented using the no till system which, besides reducing soil erosion, offers economic results from the first year of implementation through use of labor, time saved, and reduction in the number of agricultural operations, thus reducing production costs. An increase in productivity from the first harvest has also been observed. A similar situation occurs with minimum tillage. This brings us to the lesson that no till (or minimum tillage) is the ideal system to be implemented from the start of intervention in microcatchments since it achieves the basic objectives of the technical strategy of increasing coverage, increasing water infiltration and reducing surface runoff, as well as achieving the objectives (from the direct standpoint of the farmer) of reducing costs and increasing production with less risk. In 87 microcatchments assisted in western Santa Catarina, these two management systems represent 85% of areas with annual crops, which total 105,000 hectares in these microcatchments.
3.2 – Water Infiltration in Soi
l Among the factors influencing greater water infiltration in the soil, we wish to point out surface conditions in terms of degree of coverage and profile conditions, especially with regard to preserving structure, both of which are related to soil type and adopted use and management. The large increase in soil cover within the microcatchment, associated with changes in tillage, has ensured greater rainwater infiltration, as shown in Figure 1, where average levels and peak discharges are higher, thereby ensuring greater water availability in Lajeado São José.
The discharge regression equation shows there was a significant increase in terms of rain, which was to be expected since these variables are directly related.
Figure 1 – Performance of rain and discharge in Lajeado São José, Chapecó, SC, from April/88 to December/97.
The change in land use and management, particularly for direct and minimum tillage, associated with conservation-oriented support practices, has led to a significant reduction in the erosion process, as seen in the performance of the following indicators: Turbidity of water and concentration of sediments in suspension- In the waters of Lajeado São José, turbidity in the period from 1988 and 1997 was significantly reduced (61%) as observed in Figure 2 , where in 1988 the average monthly value was 130 units of turbidity, reduced to 50 units in 1997. Without considering increased rainfall, as shown above, a regression analysis was made for the turbidity variable, which detected a significant reduction during the period, as shown in the regression equation, Figure 2. The significance of the linear equation’s components were evaluated by the t test.
Considering that rainfall increased during the period, this result is more significant than that shown by the regression equation. With regard to the concentration of sediments in concentration, note that there was also a significant 69.5% reduction, when comparing 1988 average monthly values (400 mg/l) to 1997 values (112 mg/liter) as shown in Figure 3. The no till area in this microcatchment increased from 25 to 1500 ha.
Figure 2 – Performance of turbidity in waters of Lajeado São José, Chapecó SC, and rainfall from April/88 to April/97.
Figure 3 – Performance of concentration of sediments in suspension in waters of Lajeado São José, Chapecó SC, and rainfall from April/88 to December/97.
In the Rio Caçador microcatchment, municipality of Seara, SC, water turbidity values provided by CASAN from 1989 to 1998 show a 75% reduction (Figure 4). Activities in this microcatchment began in 1991, and the conservation area increased from 50 to 550 ha, with minimum tillage predominating. The microcatchment contains a total area of 3200 ha and 137 families. There was also a reduction in consumption of aluminum sulfate, accompanying the turbidity trend.
Figure 4 – Performance of turbidity in waters of Rio Caçador, municipality of Seara - SC), and consumption of aluminum sulfate from 1989 to 1998. (Source: CASAN/Chapecó).
In the Rio das Flores microcatchment, municipality of São
José do Cedro, with 3050 ha and 170 families, turbidity decreased 80%, with the
intervention of the World Bank’s Land Management II Project since 1991 (Figure 5).
The area with soil conservation increased from 750 ha in 1991 to 2000 ha in 1998, while
the number of no till planters in this period increased from 5 to 50. Of the 2000 hectares
conserved, 80% use no till. In monitored microcatchments, peak turbidity is low and less
frequent, indicating less sediment flowing into rivers. This shows that Better Management
Practices and changes in land use are having an influence on reducing erosion. 
Figure 5 – Performance of turbidity in waters of Rio das Flores, São José do Cedro/SC, from 1992 to 1998 (Source: CASAN/Chapecó).
Figure 6 – Performance of turbidity in waters of Rio Mampituba, Praia Grande/SC, from July/89 to July/98 (Source: CASAN, Criciúma/SC.
The 50% reduction in turbidity in the Rio Mampituba microcatchment is due to increased perennial crops (banana and pasture) on hillsides, thus reducing the erosion process. Low turbidity values are associated with the type of soil predominating in the microcatchment (sandy soil) where part of the sediment is washed away.
Figure 7- Performance of concentration of fecal coliform bacteria in waters Rio Guabiruba do Sul, municipality of Guabiruba/Santa Catarina.
The Rio Guabiruba microcatchment contains an area of 3000 ha. It is notable for being the largest dairy basin in the municipality of Guabiruba. The activities which are ensuring the reduction of fecal coliform bacteria are basic sanitation and storage of animal waste. In addition, erosion is controled through green manure. Studies carried out by IPH (Hydraulic Research Institute), in the Potiribu basin, in a 110 ha area in the municipality of Pejuçara, State of Rio Grande do Sul, demonstrated that the maximum concentration of sediments measured during two rainfall events was 13 g/l for the conventional soil preparation system and 3 g/l for the no till system (Figure 7).
Figure 7 – Concentration of sediments (g/l), in surface runoff in conventional preparation system and no till, Pejuçara/RS.
Total sediment loss For Lajeados São José, based on the concentration of sediments in suspension and discharge, total sediment loss was measured; for 1988/89, this was 6t/ha/year, considering annual crop area. In 1997, this loss was reduced to 5t/ha/year (Figure 6). Reduction in the loss of nutrients associated with sediments
Considering the average nutrient content in sediments collected in Lajeado São José (BASSI,1990), the 6.0 t/ha/year sediment loss in 1988 represented, in fertilizer equivalent, US$40.00 per hectare/year of lost nutrients (nitrogen, phosphorus, potassium, calcium and magnesium). With total sediment loss reduced from 6.0 to 5.0 t/ha/year, there was a consequent reduction in the loss of nutrients whose cost per hectare/year fell fromUS$40.00 to US$ 31.60.
Figure 8 – Performance of total sediment loss in waters of Lajeado São José, and rainfall from April/88 to December/97, Chapecó SC.
Reduction in water treatment cost. Besides impoverishing the soil and the farmer, erosion makes it more expensive to treat the water offered to consumers. From data obtained at CASAN/Chapecó, it was noted that the quantity of aluminum sulfate used in flocculating solids in suspension and subsequent decantation to the waters of Lajeado São José, fell from 28 g/m3 in 1991/92 to an average of 15 g/m3 in 1996. The same trend in reduced consumption of aluminum sulfate was observed in Rio Caçador, in Seara (Figure 4).
3.4 – Reduction in water contamination/pollution
As a consequence of reduced erosion, improvements in basic sanitation and more adequate management of animal waste, waters of Lajeado São José show decreasing curves in the concentration of fecal coliform bacteria at sampling points, as indicated in Figure 9; regression equations show that this reduction is significant over time.
Figure 9 – Concentration of fecal coliform bacteria at different collection points, in waters of Lajeado São José, Chapecó, SC
One of the tasks which will permit the continuity of activities under the work plan is to organize microcatchment farmers. Farmers organize for diverse reasons; historically, this custom was associated with religious and socio-cultural aspects. As a result of actions carried out in this regard in the Lajeado São José microcatchment, it was observed that farmers organize themselves into small groups to discuss their problems and seek joint means of solving them, as well as to purchase agricultural machinery and implements. The number of groups formed for various activities increased from 2 in 1990 to 27 in 1997.
The improvement in the quality of living of farmers and their families, besides being associated with environmental quality, is reflected in increased income and greater access to goods and services, for which farmers participate in generating. Through planning, farmers come to better understand, administer and manage their resources (natural, financial and labor), adjust production systems, increase the value of internal resources and make greater use of them, thereby making it possible to decrease dependency, decrease losses, reduce costs, and increase productivity, which, together with organization and better marketing, lead to improved farm income. A sampling of 5% of farms in the microcatchment was made to compare 1990 income with that of 1997, based on the performance of crop and livestock systems which comprise the production system associating grain production with the raising of poultry, hogs and dairy cattle. It was noted that there was an average increase of R$3,546.29 between 1990 and 1997, considering the farms analyzed. It is interesting to note that farmers pointed to no till as one of the main reasons for better agricultural performance.
Results clearly demonstrate that the objectives of the World Bank Land Management II Project’s technical strategy were achieved, resulting in a significant improvement in water quality, reduced soil degradation, evolution of crop productivity and increased income for rural properties. The study shows that microcatchment producers are taking important steps toward sustainable development. It was also concluded that even a simple monitoring system can only be carried out when there is a complete structure of technicians and collaborators, with laboratory support. However, without such monitoring, it would not be possible to consistently and safely evaluate the results of efforts carried out in the microcatchments.
Contents