| dc.description.abstract | The irrigated farm crops are the main users of water. With this, in places where there is a water
shortage to attend all sorts of use, this kind of activity is characterized like as a potentially conflicting,
once that to produce one hectare of rice, are necessary thousands cubic meters of water. To work out
this conflict, many actions are been developed, as giving rights and tax to use water. Although, to the
effectiveness of that actions, is necessary an effective inspection over all of the producers and users,
monitoring each volume used. Being a inspection this kind unsustainable to the manager, is necessary
the study of methodologies to determine water flow and volumes of irrigation, which shall be easily
understood and applied, to be used by the producers themselves. Were tested, comparatively, two
sorts of hydraulics systems, sharp crested Weirs and Velocimetric Hydrometers, measurers of water
flow and volumes respectively, for monitoring the volumes of irrigation of two parcels of irrigated rice in
the harvest 2009/2010, located in Cachoeira do Sul city, in Capané locality. In each parcel, one with
Direct tillage and area of 0,66 ha and another one with Conventional tillage and area of 0,80 ha, the
monitoring of water occurred simultaneously by using the Weirs and Hydrometers installed in
sequence and confined, in other words, the monitored water was the same in both systems. Was used
Pluviometer to monitoring the total volume of rain fall, in order that, with the irrigation volume was
calculated the total volume necessary to that rice parcels. The results of the comparative monitoring
between Weirs of Thin Wall and Velocimetric Hydrometers showed a small difference in the final
results, been the difference of 1,15% bigger by the Hydrometer in relation to Weir in the parcel with
Direct tillage and 6,75% smaller by Hydrometer in relation to Weir in Conventional tillage. However,
Were verified daily variations between the Weirs and Hydrometers that reached 82% in the Direct
tillage and 39% in the Conventional tillage. The total volume monitored to each parcel was 8565,15
m³/ha in the parcel with Direct tillage and 9987,25 m³/ha in the conventional tillage, both considering
the results of Weirs. With the results found and the characteristics of operation and maintenance of
the analyzed systems, is checked the availability of using sharp crested Weirs for monitoring water
quantity in rice crops, although by the comparatively study oh both systems, is not recommended to
use hydrometers in these ways. | |
