A pinboard by
Shaini Naha

Postgraduate researcher(PhD), University of Bristol


Flood forecasting in an Indian river river basin using WRF-Hydro

Floods have been recurrent phenomenon in many parts of India. Therefore Flood forecasting and mitigation is quite essential to help the decision makers to make adaptive measures.


Flood mitigation due to extreme rainfall events in the inner Bangkok, Thailand

Abstract: In the past decades, the influence of climate change has caused changes in the amount of rainfall in many areas which may affect the flood assessment and mitigation. This research aims to determine amount of rainfall which impacts on changes of the water levels in canals and evaluate the appropriate mitigation measures for floods in the inner Bangkok area, Bangkok Noi and Bangkok Yai districts of Bangkok. The maximum 1-day rainfall during 1997–2010 was determined under different return periods of 2, 5, 10, 25, 50 and 100 year. The MIKE 11 model was then applied to assess changes of the water levels in canals caused by design rainfall events for those return periods. The flood mitigation was also proposed by applying various pumping capacities and initial water levels, incorporating with building dykes and a floodgate. This study has found that the highest flood-risk areas are along Chak Phra and Bangkhunnon canals and the eastern part of Jakthong Canal while the lowest flood-risk area is Bangkok Yai district. Flood caused from the 10-year rainfall can be mitigated by building dykes with the height of 0.75 m [mean sea level (MSL)] and maintaining the initial water level of 0.70 m (MSL). Furthermore, it has also been found that flood caused from the 25-year rainfall can be mitigated by building the floodgate to prevent the flowing back water at Wat Yangsuttharam Canal. However, 50- and 100-year rainfalls seem to cause floods which are too large to mitigate.

Pub.: 04 May '14, Pinned: 12 Oct '17

Assessing the long-term hydrological services provided by wetlands under changing climate conditions: A case study approach of a Canadian watershed

Abstract: The water content of wetlands represents a key driver of their hydrological services and it is highly dependent on short- and long-term weather conditions, which will change, to some extent, under evolving climate conditions. The impact on stream flows of this critical dynamic component of wetlands remains poorly studied. While hydrodynamic modelling provide a framework to describe the functioning of individual wetland, hydrological modelling offers the opportunity to assess their services at the watershed scale with respect to their type (i.e., isolated or riparian). This study uses a novel approach combining hydrological modelling and limited field monitoring, to explore the effectiveness of wetlands under changing climate conditions. To achieve this, two isolated wetlands and two riparian wetlands, located in the Becancour River watershed within the St Lawrence Lowlands (Quebec, Canada), were monitored using piezometers and stable water isotopes (δD – δ18O) between October 2013 and October 2014. For the watershed hydrology component of this study, reference (1986–2015) and future meteorological data (2041–2070) were used as inputs to the PHYSITEL/HYDROTEL modelling platform. Results obtained from in-situ data illustrate singular hydrological dynamics for each typology of wetlands (i.e., isolated and riparian) and support the hydrological modelling approach used in this study. Meanwhile, simulation results indicate that climate change could affect differently the hydrological dynamics of wetlands and associated services (e.g., storage and slow release of water), including their seasonal contribution (i.e., flood mitigation and low flow support) according to each wetland typology. The methodological framework proposed in this paper meets the requirements of a functional tool capable of anticipating hydrological changes in wetlands at both the land management scale and the watershed management scale. Accordingly, this framework represents a starting point towards the design of effective wetland conservation and/or restoration programs.

Pub.: 18 Aug '16, Pinned: 12 Oct '17

The impacts of a changing climate on catchment water balance and forest management

Abstract: Climate change has serious impacts on forest services with regard to the spatial and temporal distribution of water within catchments. Hence, combined forest and catchment management in a changing climate is a crucial concern for people and society. To assess hydrological processes and water resources in two forested headwater catchments in south-west Germany the physical based hydrological model ArcAPEX was calibrated to investigate climate change scenarios for the near (2021–2050) and far (2071–2100) future. Even though the trend in temperature is positive in most regional climate change scenarios for south-west Germany, the precipitation trend is quite ambiguous. Different precipitation scenarios give access to the possible bandwidth between water stress and flood generation. Our results can be used to describe water resources and discharge characteristics under conditions of different land use change scenarios.Management option for a sustainable forestry and flood mitigation will be to “spread the risk” by creating forests with a high biodiversity and a prioritization of forest services and functions. The principle is to find “no-regret” decisions. In this sense, final decisions should not be taken too early, and several options should be kept open, such as dealing with increasingly frequent droughts on one hand and increased runoff generation on the other hand. Thus, it should remain possible for forest and catchment management authorities to react to possible developments in an uncertain future.

Pub.: 19 Dec '16, Pinned: 12 Oct '17