V DETERMINATION OF AVERAGE ANNUAL RAINFALL IN THE AGUABLANCA STREAM WATERSHED USING GIS AND IDW METHOD V DETERMINACIÓN DE LA PRECIPITACIÓN MEDIA ANUAL EN LA CUENCA DEL ARROYO AGUABLANCA MEDIANTE SIG Y EL MÉTODO IDW

In this investigation is analized the average annual rainfall of the hydrographic basin of the Aguablanca stream through the data provided 1 Engineering Faculty Universidad Francisco de Paula Santander, Cúcuta, Norte de Santander, Colombia Emailjavieralfonsocg@ufps.edu.co Orcid: https://orcid. org/0000-0002-9894-0177 2 Engineering Faculty Universidad Francisco de Paula Santander, Cúcuta, Norte de Santander, Colombia Emailjose.jacome@ufps.edu.co orcid: https://orcid. org/0000-0002-6022-6891 3 Universidad Francisco de Paula Santander, Cúcuta, Norte de Santander, Colombia Email: mawencyvergel@ufps.edu.co orcid: https://orcid. org/0000-0001-8285-2968 by the Institute of Hydrology, Meteorology and Environmental Studies (IDEAM) ranging from 1976 to 2016, because there aren ́t pluviometric stations relatively close, the methodology is used IDW with the intention of interporlation results and have a calculation close to reality. it ́s concluyed lhe average annual precipitation of this river is 1327.9 mm/year, a normal value for a river basin in a tropical zone, also calculating the amount of water volume, is possible to calculate the amount of evapotranspired water, parameters that vary according to temperature and type of vegetation.


INTRODUCTION
Precipitation is one of the most important parameters of the hydrological cycle, which, in turn, is one of the main sources of crop supplies, human consumption and necessary for the conservation of wildlife [3] Due to this importance, it is essential to collect all the necessary information to be able to establish hydrological models that allow a more precise understanding of the behavior of the water cycle in any study area.
A hydrological model is a set of historical data that serves to predict long-term changes in hydrological flows, where some of its uses are for: Watershed management, operation of reservoirs, water supplies, planning and design of hydraulic structures, among others [13].
Water resources are scarce and essential in all types of ecosystems [11] in such a way that the spatial distribution and temporal variability of precipitation, control the growth of vegetation and the massive transport of hydrological resources on the land surface [4]. It is for this reason that the influence of precipitation is significant in hydrology, in the environment, since it has a direct effect on types of vegetation and in turn on wildlife. Thus, obtaining accurate and reliable rainfall data becomes a crucial need to be able to make applications for the purpose of this study topic [5]. The way to measure rainfall is mainly through the use of pluviometric stations, which are well known for their installation and easy operation, in addition to the low costs that they require. When there is a considerable amount of stations, the measurements are characterized by consistent and precise measurements, where the results are used to describe the characteristics and regimes of these precipitations [7].
Climate change is one of the aspects that most concern the scientific community, since human activities, such as the burning of fossil fuels and Therefore, foreseeing this type of consequences can be achieved with an adequate management of water resources, which will also serve for disaster prevention, which must have an environmental policy with a water quality model that allows a correct handling and delivery of these resources to nature [8] [12] [14] [15].

MATERIALS AND METHODS
To calculate the average precipitation, first, the watershed of the stream of study was delimited, which is the Aguablanca stream, located in the municipality of Bochalema, in the department of Norte de Santander, in the city of Cúcuta.

V D E T E R M I N A T I O N O F A V E R A G E A N N U A L R A I N F A L L I N T H E A G U A B L A N C A S T R E A M W A T E R S H E D U S I N G G I S A N D I D W M E T H O D
For example in the above figures an approximate of 10%, 20%, 25%, 25% and 20% can be determined for the stripes that overlap the figure.
In this way it is calculated with the values of each precipitation and its percentage, obtaining an average precipitation of the basin with the following table. · 2 0 4 · Therefore, with the calculated data, precipitation can be plotted over the years studied. · 2 0 5 ·

V D E T E R M I N A T I O N O F A V E R A G E A N N U A L R A I N F A L L I N T H E A G U A B L A N C A S T R E A M W A T E R S H E D U S I N G G I S A N D I D W M E T H O D
In this way, the following table is obtained with the relevant data for each year and its precipitation value. Table 5. Average multiannual precipitation of the Aguablanca stream basin.

PREC. PROM YEAR PREC. PROM YEAR
An arithmetic average is then taken, which is simply the sum of all rainfall divided by the total number of years.

CONCLUSIONS
The average annual precipitation of this river basin was successfully calculated using the IDW (1) (2) ge is then taken, which is simply the sum of all rainfall divided by the total number · 2 0 6 ·