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Mangrove restoration projects, aimed at restoring important values of mangrove forests after degradation, often fail because hydrological conditions are disregarded. We present a simple, but robust methodology to determine hydrological suitability for mangrove species, which can guide restoration practice. In 15 natural and 8 disturbed sites (i.e. disused shrimp ponds) in three case study regions in south-east Asia, water levels were measured and vegetation species composition was determined. Using an existing hydrological classification for mangroves, sites were classified into hydrological classes, based on duration of inundation, and vegetation classes, based on occurrence of mangrove species. For the natural sites hydrological and vegetation classes were similar, showing clear distribution of mangrove species from wet to dry sites. Application of the classification to disturbed sites showed that in some locations hydrological conditions had been restored enough for mangrove vegetation to establish, in some locations hydrological conditions were suitable for various mangrove species but vegetation had not established naturally, and in some locations hydrological conditions were too wet for any mangrove species (natural or planted) to grow. We quantified the effect that removal of obstructions such as dams would have on the hydrology and found that failure of planting at one site could have been prevented. The hydrological classification needs relatively little data, i.e. water levels for a period of only one lunar tidal cycle without additional measurements, and uncertainties in the measurements and analysis are relatively small. For the study locations, the application of the hydrological classification gave important information about how to restore the hydrology to suitable conditions to improve natural regeneration or to plant mangrove species, which could not have been obtained by estimating elevation only. Based on this research a number of recommendations are given to improve the effectiveness of mangrove restoration projects.

Purpose: Rain storm events mobilise large proportions of fine sediments in catchment systems. 28 Sediment from agricultural catchments are often adsorbed by nutrients, heavy metals and other 29 (in)organic pollutants that may impact downstream environments. To mitigate erosion, 30 sediment transport and associated pollutant transport it is crucial to know the origin of the 31 sediment that is found in the drainage system and, therefore, it is important to understand 32 catchment sediment dynamics throughout the continuity of runoff events. 33 Materials and methods: To assess the impact of the state of a catchment on the transport of 34 fine suspended sediment to catchment outlets an algorithm has been developed which classifies 35 rain storm events into simple (clockwise, counterclockwise) and compound (figure-of-eight; 36 complex) events. This algorithm is the first tool that uses all available discharge and suspended 37 sediment data and analyses these data automatically. A total of 797 runoff events from three 38 experimental watersheds in Navarre (Spain) were analysed with the help of long-term, high 39 resolution discharge and sediment data that was collected between 2000-2014. 40 Results and discussion: Morphological complexity and in-stream vegetation structures acted 41 as disconnecting landscape features which caused storage of sediment along the transport 42 cascade. The occurrence of sediment storage along transport paths was therefore responsible 43 for clockwise hysteresis due to the availability of in-stream sediment which could cause the 44 "first flush" affect. Conversely, the catchment with steeper channel gradients and a lower 45 stream density showed much more counterclockwise hysteresis due to better downstream and 46 lateral surface hydrological connectivity. In this research hydrological connectivity is defines 47 as the actual and potential transfer paths in a catchment. The classification of event SSC-Q 48 hysteresis provided a seasonal benchmark value to which catchment managers can compare 49 runoff events in order to understand the origin and locations of suspended sediment in the 50 3 catchment. 51 Conclusions: A new algorithm uses all available discharge and suspended sediment data to 52 assess catchment sediment dynamics. From these analysis, the catchment connectivity can be 53 assessed which is useful to develop catchment land management.

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