For the simulation of the 39-year period, the
values x1,x2,x3,x4 of the validation were used; of
these results a revalidation was carried out to improve
the data by accommodating in a quadratic equation of
second degree, obtaining Figure 7 the record of flows
at the daily level, in Figure 8 the registration of flows
at the monthly level, in Figure 9 the correlation R2 =
0.8805 is shown; then, it follows that the GR4j
method was properly adjusted, since the correlation is
very close to 1; There is also little variability between
measured and recorded flows.
Figure 7 shows the maximum flows generated
with the GR4j method during the periods that the El
Niño phenomenon occurred in the last 40 years, these
being in the periods: i) 1982-1983, a maximum flow
of 132.50 m3/s on the date 02/10/1982, ii) 1997-1998,
a maximum flow of 276.51 m3/s was recorded on the
date 02/8/1998 and iii) 2017-2018, a maximum flow
of 305.71 m3/s was recorded on 03/15/2017; from
which it can be deduced that in the Cañete River basin
the El Niño phenomenon had the greatest impact in
the period 2017-2018 and the least impact in the
period 1982-1983.
5 CONCLUSIONS
It can be concluded that the GR4j model was properly
applied for the estimation of daily and monthly flows
in the Cañete River basin to the Putinza hydrometric
station resulting in a satisfactory representation of the
series of daily flows. Also, allowing to reconstruct
past historical records using the grid data of
precipitation and temperature ERA5 for the period
1980 – 2019.
The GR4j method can serve as a basis for other
studies in other basins to generate extensive flow
records over time, since it uses four main variables.
The flows generated by this method can be used
in the planning of various hydraulic and civil projects,
such as irrigation works for agricultural land,
construction of bridges, taking into account the
Putinza hydrometric station.
The area surrounding the sub basin of Cañete
towards the Putinza station, has been roughed 3 times
in the last 40 years by the El Niño phenomenon, this
phenomenon has caused structural havoc to the
population, this because there is no hydrological
study that can serve as a basis for a correct design of
riparian defense, That is why it is expected that the
present work will serve as a reference for the
compilation of necessary information to be able to
plan projects that meet the needs of the population.
The values of the Nash efficiency criterion for
calibration and validation are 86.5% and 84.4%
respectively. Both values are within an excellent
range demonstrating that the model was adjusted
properly.
Bilan's criteria values for calibration and
validation are 96.3% and 105.9% respectively,
showing optimal model performance.
The graph for monthly flows will also allow us to
estimate the monthly prorated distribution over an
extended period of the year, which will give us a
better idea of the monthly profile distribution.
REFERENCES
Andina Peruvian News Agency. (2017). Cañete River
could exceed its flood threshold in the following days.
https://andina.pe/agencia/noticia-rio-canete-podria-
sobrepasar-su-umbral-inundacion-siguientes-dias-
744688.aspx
Public Eye. (2017). El Niño phenomenon: three decades of
death and destruction in Peru. Public Eye. https://ojo-
publico.com/404/las-cifras-historicas-del-fenomeno-
del-ni%C3%B1o-en-peru
Development Bank of Latin America. (2000). The lessons
of El Niño. Peru. CAF. http://scioteca.caf.com/
handle/123456789/676
Government of Peru. (2022). El Niño phenomenon.
https://www.gob.pe/9297-fenomeno-el-nino
Lujano, E., Sosa, J. D., Lujano, R., & Lujano, A. (2020).
Performance evaluation of hydrological models GR4J,
HBV and SOCONT for the forecast of average daily
flows in the Ramis River basin, Peru. UC
ENGINEERING Magazine, 27(2): 189-199.
Rodríguez Cárdenas, F. E., & Rodríguez Villalba, A. J.
(2021). Comparison of rain-runoff hydrological
models GR2M and GR4J in obtaining average flows
in the Subachoque river basin. https://
repositorioslatinoamericanos.uchile.cl/handle/2250/34
30054
Carmona A. (2021). Code Google Earth Engine.
https://code.earthengine.google.com/ce29e6d1d05079
dfac0063043b3be4c5
National Water Authority (2021). Water Observatory.
National Water Resources Information System.
https://snirh.ana.gob.pe/observatorioSNIRH/
Pucha-Cofrep, F., Fries, A., Cánovas-García, F., Oñate-
Valdivieso, F., González-Jaramillo, V., & Pucha-
Cofrep, D. (2017). GIS fundamentals: Applications
with ArcGIS.
Carvajal, L. F., & Roldán, E. (2007). Calibration of the
rain-runoff model added GR4J application: Boring
river basin. Dyna, 74(152), 73-87.
Molnar, P. (2011). Calibration. Watershed Modelling, SS
2011. Institute of Environmental Engineering, Chair of
Hydrolgy and Water Resources Management, ETH
Zurich, Switzerland.