Delivery of sediment through such canal networks thus mimics and enhances the yearly flood sediment pulses (Day et al., 1995 and Day et al., 2011) at a rate that is similar to the fast growing juvenile stages of fluvial dominated deltas (e.g., Jerolmack, 2009) when channel density is at maximum. Careful design of the depth and cross-section for such canal networks should be able Bortezomib to optimize the amount of fines trapped on the plain to counteract the upstream decline in sediment load and/or

changes in flood regime. However, the question is if enough sediment exists now in the Danube to counteract sea level rise? Based on our analysis, the 10% of the present Danube load (i.e., 2.5 MT/yr) transiting the interior of the delta needs to be increased 4–8 times to fully maintain accretion in the internal Danube delta (i.e., ∼2000 km2 without considering the polder regions and ignoring the coastal region) at rates higher or equal to the present sea level rise of 3 mm/yr (Cazenave et al., 2002). However, the effective need of fluvial sediment for the internal delta plain could be significantly lower when organic sedimentation is taken into account (Reed, 1995, Kirwan and Temmerman, 2009 and Lorenzo-Trueba et al., 2012). Some similar positive results come from channelization on the small agricultural selleck compound Pregnenolone delta of

the Ebro, where canals for rice cultivation have captured suspended sediments at rates keeping up or above the contemporary sea level rise (Ibáñez et al., 2010 and Day et al., 2011) or from localized experiments in large deltas such as the Ganges-Brahmaputra (Sengupta, 2009). Although we are not aware of comprehensive studies on this topic, dense channelization has occurred in many deltas around the world (e.g., Nile, Mekong,

Red River to name a few) and they may have had similar effects on delta plain accretion. For example, it is known that the intricate canal network for irrigation on the Nile delta captures almost all sediments coming down the Nile after the Aswan Dam (Stanley and Warne, 1998). And on the Mississippi, upstream diversions (e.g., Blum and Roberts, 2009) would be directed toward delta plain maintenance by augmenting accretion rather than primarily build land anew as proposed for the lower Mississippi delta plain. However, cutting of canals by the oil industry on the Mississippi delta plain without a regular infusion of suspended sediments from the river has had instead destructive effects on the marshes of that delta (e.g., Turner, 1997). While ecological analysis is beyond the scope of the present work, it is clear that the ecological effects of channelization must be carefully considered (Day et al., 2007).