Groundwater, flooding and hydrological functioning in the Findhorn floodplain, Scotland

A large floodplain of the River Findhorn, northeast Scotland, was investigated using hydrogeological and hydrochemical methods (including residence time indicators) to characterise groundwater/surface-water coupling and groundwater flooding. The study demonstrated widespread stratification within the floodplain: shallow (30 mm). Persistent groundwater flooding occurs within topographical lows and also in the discharge zone where it is largely managed with a series of drains constructed in the 19th century. The significant and complex role of groundwater in floodplains, demonstrated by this study, highlights the importance of fully considering groundwater in flood management schemes

Glaciotectonic disintegration of roches moutonnées during glacial ripping in east Sweden

Roches moutonnées are typical landforms of glacial erosion developed in hard rocks, with an asymmetric profile caused by abrasion and lee-side plucking. In eastern Sweden, some roches moutonnées show extensive damage, including open fractures, disintegration into blocks, fracture caves and short boulder trains. Disintegration increases along ice-flow directions during deglaciation of the last Weichselian Fennoscandian Ice Sheet, indicating a subglacial origin: limited edge rounding can be explained by a combination of hard rock, slow abrasion rates and disintegration just prior to deglaciation. The roches moutonnées initially developed in kernels of gneissic rocks with a wide fracture spacing (large block size) and interlocking fracture pattern, and hence high overall rock mass strength. Dilated fractures and ‘fracture caves’ occur up to 15 m below the ice-bed interface. It is proposed that hydraulic jacking by overpressured water opened up the rock mass along pre-existing fractures. Jacking reduced rock mass strength, allowing glaciotectonic deformation of the roches moutonnées. Uneven hydraulic jacking led to uplift of individual fracture-bound blocks above the pre-existing smooth, abraded surface of the roches moutonnées, creating blunt, step-like edges. These edges allowed high ice pushing forces to act on large blocks: where blocks extend into the deeper rock mass, they further aided the disintegration of the rock mass. The disintegrated roches moutonnées can be regarded as transient features between intact bedrock and complete disintegration into boulders. The jacking-disintegration-transport sequence is characteristic of glacial ripping and very different from classic lee-side plucking

Global CO2 emissions from dry inland waters share common drivers across ecosystems

Many inland waters exhibit complete or partial desiccation, or have vanished due to global change, exposing sediments to the atmosphere. Yet, data on carbon dioxide (CO2) emissions from these sediments are too scarce to upscale emissions for global estimates or to understand their fundamental drivers. Here, we present the results of a global survey covering 196 dry inland waters across diverse ecosystem types and climate zones. We show that their CO2 emissions share fundamental drivers and constitute a substantial fraction of the carbon cycled by inland waters. CO2 emissions were consistent across ecosystem types and climate zones, with local characteristics explaining much of the variability. Accounting for such emissions increases global estimates of carbon emissions from inland waters by 6% (~0.12 Pg C y−1). Our results indicate that emissions from dry inland waters represent a significant and likely increasing component of the inland waters carbon cycle

Groundwater, flooding and superficial deposits in the Findhorn catchment

The Forres area in north-east Scotland was subjected to one of the most catastrophic floods in UK history when the River Findhorn flooded in 1829. In recent times, Forres has also flooded to a lesser extent (notably in 1997 and 2001) and a series of flood alleviation schemes have been designed to help protect the town. This has enabled a detailed examination of the role of groundwater within the floodplain. Detailed 3D geological characterisation and modelling, pumping tests, water-level monitoring and environmental tracers have been used to characterise groundwater flow within the superficial deposits. A detailed groundwater model has been developed using the ZOOM suite of models to further investigate groundwater/surface water interactions and groundwater flooding. The research has demonstrated that there is significant groundwater storage and flow within the thick and complex superficial deposits in the River Findhorn floodplain which is closely coupled to surface water. Consequently, the flood alleviation schemes have been modified to balance protection from surface water flooding and from groundwater flooding

Least cost land-use changes for targeted catchment salt load and water yield impacts in south eastern Australia

This study reports an analysis of the economics of options for strategic land-use change to attain future catchment level target combinations of salt load and water yield. Farm level survey information on land use, productivity, prices and costs of production were integrated with spatially specific soil, rainfall, topography, hydrology and salinity results of the simulation model CAT (Catchment Analysis Tool). This information was used to populate a two stage economic optimization model in which subcatchment economic results were combined for catchment level analyses. This study is the first to exploit CAT results in an economic framework and the first in which economic results are mapped using CAT. The 64,000ha Bet Bet Catchment in Victoria, Australia, once deemed among the highest priority areas in the Murray Darling Basin for dryland salinity reduction, is the focus of this study. The calculated current net present value (NPV) of agricultural production in the catchment is AU$78 million3 while providing 42 GL of water yield4 annually for use downstream with a salt load of 22,600t. Results show that salt loads may be reduced to 18,600t (reduction of 4000t) through expansion of tree plantations and lucerne production, reducing water yield to 31 GL (11 GL reduction) and NPV to AU$ 63 million (AU$15 million reduction). Water yields could be increased from current levels by 2 GL while maintaining current salt loads. Alternatively, catchment NPV could be increased by approximately AU$ 7 million with little or no reduction in water yield; but there may be reasons (small farm size) why this is unlikely. For this catchment, the maximum reduction in salt load appears insufficient to justify public investment in tree planting and perennial pasture establishment, particularly when the reduced NPV and reduced water yields are taken into account. The results for this catchment do not support regulation of land use for the sake of lowering river salinity. However, the capacity of tree plantations to reduce water yields may support a regulation requiring purchase of water entitlements from downstream entitlement holders for new plantations. Despite millions of dollars of past public investment, it is now clear that Bet Bet Catchment was never one where land-use changes could benefit downstream water users. The approach described in this paper enables catchment management authorities to weigh costs of land-use change against downstream benefits and natural resource management (NRM) options elsewhere.Land-use Economic optimisation Salinity Environmental service Hydrology Simulation Farm survey Forest plantation

P3‐153: Surgery using general anesthesia and risk of dementia in the Aging, Demographics and Memory Study

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/152843/1/alzjjalz2009041027.pd