On the sensitivity of tidal network characterization to power law estimation

ABSTRACT. Long-term simulations (3000 yr) of an idealized basin using different tidal ranges (1, 2 and 3 m) and grain sizes (120, 480 and 960 μm) have been performed in order to cover a range of hydrodynamic and sedimentary conditions. Two different cell sizes (50 and 100 m) have been used to study the impact of cell size on tidal network development. The probability distributions of the drainage area and the drainage volume have been computed for every simulation (during an ebb and a flood phase). Power law distributions are observed in drainage area and drainage volume distribution. As an objective estimation of the exponent of a power law is an open issue, different approaches (linear binning, normalized logarithmic binning, cumulative distribution function and maximum likelihood) proposed by White et al. (2008) to estimate the exponent have been used to carry out a sensitivity analysis. Our findings indicate that although all methods results in high and significant correlation coefficients, more work is needed to develop a universal, objective estimation of the exponent

Restauración hidrodinámica del Molino de Mareas de Santa Olaja (Estuario de Joyel en Cantabria)

Este trabajo ha sido financiado por la Comisión Europea en el marco del proyecto CONVIVE-LIFE (LIFE14 NAT/ES/001213)

Restoration activities and implications for tidal network scaling characteristics

RESUMEN: El objetivo general es avanzar en el conocimiento del funcionamiento de los sistemas estuarinos y mejorar nuestra capacidad de gestionarlos de una manera sostenible. Es por ello que en el capítulo 1 se desarrolla una metodología para ayudar a los gestores en la toma de decisiones y priorizar las acciones de restauración basándose en los efectos morfodinámicos que cada acción puede ocasionar en el estuario. Uno de los elementos morfodinámicos estudiados son los canales mareales, que desempeñan un papel clave en la hidrodinámica del sistema y por lo tanto en el intercambio de sustancias que entran y salen del estuario. Es por ello que cobra gran relevancia la forma en el que el volumen de agua se distribuye por el sistema, es decir la distribución de la red de drenaje. En los capítulos 2 y 3 se estudia la evolución y organización de esta red de canales (red de drenaje), tratando de determinar la existencia de posibles relaciones de escala en diversas características de la red de drenaje del estuario. Estas características de escala se muestran como una medida estadística representativa de las propiedades geométricas del sistema que no dependan de los detalles específicos del sistema. Una vez explorada la caracterización estadística de la estructura de una red de drenaje en un sistema mareal, en el capítulo 4 se realiza un ejercicio teórico que tiene como objetivo analizar como esa estructura se ve afectada por diferentes acciones de restauración.ABSTRACT: The general objective of the thesis is to advance in the understanding of the behavior if estuarine systems and improve our capabilities to manage them in a sustainable way. It is for this reason that in chapter 1 a new methodology has been developed in order to help managers and decision makers to prioritize the restoration actions based on the morphodynamics effect that each action may induce in the recovery of the estuary. One of the morphodynamic elements studied are the tidal channels, which play a key role in the hydrodynamic of the system and therefore the exchange of substances into and out of the estuary. Therefore becomes very relevant how the volume of water through the system is distributed, ie the distribution of drainage network. For this reason in Chapters 2 and 3 the evolution and organization of channel network (drainage network) has been studied, trying to determine the existence of scaling relationships in several features that can characterize the drainage network in the estuary. These scale relationships will be shown to be a representative statistical measure of estuarine geometric properties that do not depend on the specific details of the estuary. Having explored that statistical characterization of a tidal system drainage network, in chapter 4 a theoretical analysis has been performed which aims to analyzed how this statistical structure is affected by the different restoration actions