Impact of climate change on floodplain inundation and hydrological connectivity between wetlands and rivers in a tropical river catchment

Abstract

Surface water connectivity between waterbodies in a river–floodplain system is considered one of the key determinants of habitat quality, biodiversity and ecological integrity. This manuscript presents results from an investigation into the potential changes in floodplain inundation and connectivity between wetlands and rivers under projected future climates, in a large river catchment in Western Australia. The study was conducted using a two‐dimensional hydrodynamic model (MIKE 21), and the modelling domain included the floodplain reaches encompassing the ecologically important wetlands. A lumped rainfall–runoff model (SIMHYD) was used to estimate local runoff and inflows from ungauged catchments. A SRTM derived 30‐m elevation data was used to parameterize land topography and stream networks in the hydrodynamic model. Hydraulic roughness parameters were estimated using a land cover map, which was developed using a combination of aerial photography, topographic maps and Google Earth imagery. The hydrodynamic model was calibrated using stream gauge data and flood inundation maps derived from Moderate Resolution Imaging Spectroradiometer imagery. Model simulated stage heights were combined with land topography to identify floodplain pathways that connect wetlands with rivers. The connectivity of 30 off‐stream wetlands was evaluated under present and future climates. The duration of connection of the individual wetlands to the main river channel varied from 1 to 40 days depending on flood magnitude and duration. Topographic relief, location on the floodplain and magnitude and duration of the flood were found to be key factors governing the level of connectivity, and the relationship between return period of flood and inundated area was found to be non‐linear. Modelling under a drier future climate indicated that the duration of connectivity of wetlands could be up to 20% less than under the current climate, whilst under a wetter climate the connectivity could be 5% longer. The results of this study provide potential use for future studies on movement and recruitment patterns of aquatic biota, wetland habitat characteristics and water quality and wetland biodiversity assessment. Copyright © 2015 John Wiley & Sons, Ltd.

Evaluating Annual Maximum and Partial Duration Series for Estimating Frequency of Small Magnitude Floods

“…While large floods are usually responsible for channel avulsions, levee breaches, and transporting large bed-load sediments, frequent floods (e.g., recurrence interval of one or two years) are primarily responsible for controlling channel morphology because of their frequent nature and ability to erode and transport large volumes of fine sediment. Frequent floods are especially important for riparian and aquatic biodiversity [4][5][6][7][8]. Frequent, low-magnitude floods also indirectly shape communities by acting as a disturbance agent by altering nutrient distribution, rearranging sediment and removing individual organisms, creating patchiness that fosters biodiversity [9].…”

Interactions between Lake-Level Fluctuations and Waterlogging Disasters around a Large-Scale Shallow Lake: An Empirical Analysis from China

“…We select the MIKE software, which was developed by the Danish Hydrological Institute [43] and has been applied widely [25,33,34], as a modeling tool to establish the NLFWSM. The MIKE 11, MIKE 21, and MIKEFLOOD modules were used to model the flood routing of tributary rivers, waterlogging and lake flow inundation, and water exchanges between the lakeside, rivers, and Nansi Lake, respectively.…”

“…Bisht et al [25] combined the SWMM, MIKE ERBAN (a model developed by Danish Hydrological Institute), and MIKE21 to simulate rainstorm waterlogging in West Bengal, India. Hydrodynamic models can obtain flooding and waterlogging information with a high spatial resolution, and have become an effective tool for simulating and predicting the flooding processes in recent years [33,34]. Several scholars have used hydrodynamic models to simulate the flooding of rainstorm waterlogging in different areas based on multi-scenario simulations to access the risks and the law of the waterlogging [17,35,36].However, there are very few reports that feature quantitative analyses of the influences of WLFs on waterlogging around lakes from the whole basin perspective by multi-scenario modeling [37].…”

Sedimentation of overbank floods in the confined complex channel–floodplain system of the Lower Yellow River, China

“…Floodplain sedimentation rates vary with the frequency, duration, magnitude and suspended sediment concentration (SSC) of floods (Alexander & Prior, ; Asselman and Middlekoop, ; Brown, ; Gomez, Mertes, Philips, Magilligan, & James, ; Harrison, Dunne, & Fisher, ; James, ; Karim et al, ; Marriott, ; Magilligan, Philips, James, & Gomez, ; Maurice‐Bourgoin, Martinez, Grelaud, Filizola, & Boaventura, ), the degree of river training (Wu, Wang, Ma, & Zhang, ), and many other factors (e.g., Aalto et al, ). When the effects of human activities are significant, however, very different floodplain sedimentation rates can be produced.…”

“…1983; Gomez, Mertes, Philips, Magilligan, & James, 1995;Harrison, Dunne, & Fisher, 2015;James, 1985;Karim et al, 2016;Marriott, 1992;Magilligan, Philips, James, & Gomez, 1998;Maurice-Bourgoin, Martinez, Grelaud, Filizola, & Boaventura, 2005), the degree of river training (Wu, Wang, Ma, & Zhang, 2005), and many other factors (e.g., Aalto et al, 2003). When the effects of human activities are significant, however, very different floodplain sedimentation rates can be produced.…”