**7. References**

	- [3] Rabunal, J. R., Puertas, J., Suarez, J., and Rivero, D. (2006) Determination of the unit hydrograph of a typical urban basin using genetic programming and artificial neural networks Hydrological Processes, vol. 21, Issue 4, pp.476-485

**Chapter 11** 

© 2012 Arganis et al., licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

© 2012 Arganis et al., licensee InTech. This is a paper distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

**Comparison Between Equations Obtained by** 

**Genetic Programming to Approach Measured** 

M.L. Arganis, R. Val, R. Domínguez, K. Rodríguez, J. Dolz and J.M. Eaton

The Ebro River is located in north-eastern Spain. After crossing the Catalan coastal mountain system, the Ebro reaches the sea. Along the lower part of the river, about 100 km from the mouth, there is a system of three reservoirs: Mequinenza (1500 hm3), Ribarroja (210 hm3) and Flix (11 hm3). These reservoirs regulate the hydrologic regime of the lower part of the river until it reaches the sea. The Mequinenza and Ribarroja reservoirs were finished in the late 1960s (in 1966 and 1969, respectively), while the Flix reservoir was completed in 1945. About 5 km downstream from the Flix reservoir is the Ascó nuclear power plant,

Ascó Nuclear Power Station, located on the Ebro River in Spain (Figure 1), takes river water for cooling purposes. The temperature of discharged water must be less than 13 ºC, however five kilometers downstream a water temperature of nearly 14ºC was estimated and such an anomaly was reported to the nuclear center. A detailed analysis shows the relationship between water temperature variation and the presence of a cascade dam system upstream of the Ascó Nuclear Power Station. Water temperature decreases downstream in the outlets of cascade dam systems [1]. During the winter period there also exists thermal stratification within the river, whereby water temperatures near deep intake areas are considerably less than the ambient temperature. Such a situation impacts water taken for cooling purposes by

Throughout the years, the human being has made use of fluvial ecosystems. Some actions

have caused changes in the thermal regimes of rivers (eg. [2 ,3]).

**Means of Multiple Linear Regression and** 

**Climatic Data in a River** 

Additional information is available at the end of the chapter

which began its activity in December 1984 [1].

http://dx.doi.org/10.5772/50556

Ascó Nuclear Power Station.

**1. Introduction** 

