VEGETABLE COVERING INFLUENCE OVER THE HYDRIC CONDITIONS OF THE RPPN-BULCÃO FARM IN AIMORÉS

SOUZA, P.H.1, VIEIRA, J.L.1

ABSTRACT
This work was carried out at the RPPN- Bulcão Farm in Aimorés - MG and aimed to assess the influence of the recovered vegetation covering over the local hydric conditions. On the RPPN - Bulcão Farm the vegetal covering is the original one from the Atlantic Forest, which due to human activities from the past was almost entirely suppressed. The work methodology was done by measuring the flow rates in ten different points, distributed in the basins of the Bulcão and Constância streams.

To evaluate the behavior of the flow throughout the day were performed flow measurements three times per day and at pre-defined times. The point of measurement studied is located at the Bulcão Stream, on the bridge which gives access to the nursery of native plants. This stage of work was done in two steps. The first one between the days of August, 29th and September, 1st, 2007 and the other one between the days of September, 26th and September 28th, 2007. It was also assessed the physical, chemical and biological water quality.

The data, provided by the automatic weather station in the city of Aimorés, available on the site of the National Institute of Meteorology, also served as basis for analyzes. The flow rates achieved in 2006 and 2007 did not differ markedly, except for the new dam where the flow was more than five times lower in 2007 compared to the previous year.

The bamboo spring, flowing of the creek Constância, in 2006 and 2007, from all points studied, presented the lowest flow. The flow of all springs had a more or less linear behavior, with small changes in values over the period of measurement. The Constância spring kept a constant flow during the period of the survey. As to the point of collection on the bridge which gives access to the nursery at the Bulcão stream, the data showed a considerable sway, ranging from 4200 L / h to 3000 L / h.

This behavior had an inverse relationship with the flow measures in the new dam, springs from the nursery, the corral, cajazinho and sapucaia, all flowing directly from the Bulcão stream, the amount of this point. The flow measured at each time had a growing reduction within each batch, with the highest values occurring in the first measurement (7:15 am) and the lowest value in the third measurement (5:15 pm). The spring of the corral was the only one that showed presence of fecal coliform term tolerant.

The results and observations made in this work showed that:

• The existing vegetation cover at the RPPN has direct and positive influence on the quality, quantity and availability of its waters;
  
  
• There was a significant improvement in water quality of RPPN between the years 2006 and 2007, given that from the eight springs studied, five showed no presence of fecal coliform bacteria in its waters;
  
  
• The amount of water available at the Bulcão stream was higher in the morning hours decreasing towards the end of the day on the basis of evaporation by transpiration and direct evaporation of the pool;
  
  
• The water quality of the Bulcão and Constância streams, without any treatment, is not consistent with the patterns of drinking, however, it may have several other uses.