Kochi,India case study of climate adaptation to floods: Ranking local government investment options

Climate adaptation is uniquely linked to location, making it predominantly a local government and community responsibility. Despite the obligation to act, local governments are hindered by the absence of applicable guides to adaptation decision-making, especially adaptation to extreme events. In this paper, we describe a framework for prioritising adaptation options that could be locally implemented and illustrate it with a study of flooding in Kochi: a city in southern India. Unlike many demand driven, economics based studies, our new framework also incorporates non-economic dimensions of the extremes and potential adaptation options. Local knowledge is used to tackle data gaps and uncertainty related to extreme events: local experts select adaptation options that offer additional benefits besides those related to climate change. These co-benefits aid decision making under uncertainty by giving weight to community priorities. The Indian case study reveals that, risk evaluation and reduction need to be locally contextualised based on resources available, immediate community requirements, planning periods and local expert knowledge. Although there will be residual damage even after implementing selected options, we argue that, climate response will be most likely to be accepted when it also supports pressing needs.     

Transitions toward co-management: The process of marine resource management devolution in three east African countries

Communities are increasingly empowered with the ability and responsibility of working with national governments to make decisions about marine resources in decentralized co-management arrangements. This transition toward decentralized management represents a changing governance landscape. This paper explores the transition to decentralisation in marine resource management systems in three East African countries. The paper draws upon expert opinion and literature from both political science and linked social-ecological systems fields to guide exploration of five key governance transition concepts in each country: (1) drivers of change; (2) institutional arrangements; (3) institutional fit; (4) actor interactions; and (5) adaptive management. Key findings are that decentralized management in the region was largely donor-driven and only partly transferred power to local stakeholders. However, increased accountability created a degree of democracy in regards to natural resource governance that was not previously present. Additionally, increased local-level adaptive management has emerged in most systems and, to date, this experimental management has helped to change resource user's views from metaphysical to more scientific cause-and-effect attribution of changes to resource conditions.     

Spatial and temporal infiltration dynamics during managed aquifer recharge

Natural groundwater recharge is inherently difficult to quantify and predict, largely because it comprises a series of processes that are spatially distributed and temporally variable. Infiltration ponds used for managed aquifer recharge (MAR) provide an opportunity to quantify recharge processes across multiple scales under semi-controlled conditions. We instrumented a 3-ha MAR infiltration pond to measure and compare infiltration patterns determined using whole-pond and point-specific methods. Whole-pond infiltration was determined by closing a transient water budget (accounting for inputs, outputs, and changes in storage), whereas point-specific infiltration rates were determined using heat as a tracer and time series analysis at eight locations in the base of the pond. Whole-pond infiltration, normalized for wetted area, rose rapidly to more than 1.0 m/d at the start of MAR operations (increasing as pond stage rose), was sustained at high rates for the next 40 d, and then decreased to less than 0.1 m/d by the end of the recharge season. Point-specific infiltration rates indicated high spatial and temporal variability, with the mean of measured values generally being lower than rates indicated by whole-pond calculations. Colocated measurements of head gradients within saturated soils below the pond were combined with infiltration rates to calculate soil hydraulic conductivity. Observations indicate a brief period of increasing saturated hydraulic conductivity, followed by a decrease of one to two orders of magnitude during the next 50 to 75 d. Locations indicating the most rapid infiltration shifted laterally during MAR operation, and we suggest that infiltration may function as a "variable source area" processes, conceptually similar to catchment runoff.     

Effect of temporal resolution of water level and temperature inputs on numerical simulation of groundwater–surface water flux exchange in a heavily modified urban river

Groundwater interacts with surface water features nearly in all types of landscapes. Understanding these interactions has practical consequences on the quantity and quality of water in either system, because the depletion or contamination of one of the systems will eventually affect the other one. Many studies have shown that the use of heat as natural tracer in conjunction with water level measurements is an effective method for estimating water flow (fluxes) between groundwater and surface water. A number of studies have explored the effects of spatial and temporal variability of groundwater–surface water flux exchanges using temperature and water level measurements; however, the effect of temporal resolution of water level and temperature data on estimating flux remains unexplored. Therefore, this study investigated the effect of temporal resolution of input data on temporal variation of groundwater–surface water flux exchanges. To this end, we calibrated a variably saturated two‐dimensional groundwater flow and heat transport model (VS2DH) at hourly and daily time scales using temperatures measured at multiple depths below the riverbed of the Zenne River, located at a well‐known Belgian brownfield site. Results of the study showed that the computed water flux through the streambed ranged between ?32 mm/day and +25 mm/day using the hourly model and from ?10 mm/day to ?37 mm/day using the daily model. The hourly model resulted in detecting reversal of flow direction inducing short‐term surface water flow into the streambed. However, such events were not captured if daily temperature and water level measurements were used as input. These findings have important implications for understanding contaminant mass flux and their attenuation in the mixing zone of groundwater and surface water. Copyright © 2012 John Wiley & Sons, Ltd.     

Assessment of Managed Aquifer Recharge Site Suitability Using a GIS and Modeling

We completed a two‐step regional analysis of a coastal groundwater basin to (1) assess regional suitability for managed aquifer recharge (MAR), and (2) quantify the relative impact of MAR activities on groundwater levels and sea water intrusion. The first step comprised an analysis of surface and subsurface hydrologic properties and conditions, using a geographic information system (GIS). Surface and subsurface data coverages were compiled, georeferenced, reclassified, and integrated (including novel approaches for combining related datasets) to derive a spatial distribution of MAR suitability values. In the second step, results from the GIS analysis were used with a regional groundwater model to assess the hydrologic impact of potential MAR placement and operating scenarios. For the region evaluated in this study, the Pajaro Valley Groundwater Basin, California, GIS results suggest that about 7% (15 km²) of the basin may be highly suitable for MAR. Modeling suggests that simulated MAR projects placed near the coast help to reduce sea water intrusion more rapidly, but these projects also result in increased groundwater flows to the ocean. In contrast, projects placed farther inland result in more long‐term reduction in sea water intrusion and less groundwater flowing to the ocean. This work shows how combined GIS analysis and modeling can assist with regional water supply planning, including evaluation of options for enhancing groundwater resources.     

The predictability of near-coastal currents using a baroclinic unstructured grid model

A limited domain, coastal ocean forecast system consisting of an unstructured grid model, a meteorological model, a regional ocean model, and a global tidal database is designed to be globally relocatable. For such a system to be viable, the predictability of coastal currents must be well understood with error sources clearly identified. To this end, the coastal forecast system is applied at the mouth of Chesapeake Bay in response to a Navy exercise. Two-day forecasts are produced for a 10-day period from 4 to 14 June 2010 and compared to real-time observations. Interplay between the temporal frequency of the regional model boundary forcing and the application of external tides to the coastal model impacts the tidal characteristics of the coastal current, even contributing a small phase error. Frequencies of at least 3 h are needed to resolve the tidal signal within the regional model; otherwise, externally applied tides from a database are needed to capture the tidal variability. Spatial resolution of the regional model (3 vs 1 km) does not impact skill of the current prediction. Tidal response of the system indicates excellent representation of the dominant M ₂ tide for water level and currents. Diurnal tides, especially K ₁, are amplified unrealistically with the application of coarse 27-km winds. Higher-resolution winds reduce current forecast error with the exception of wind originating from the SSW, SSE, and E. These winds run shore parallel and are subject to strong interaction with the shoreline that is poorly represented even by the 3-km wind fields. The vertical distribution of currents is also well predicted by the coastal model. Spatial and temporal resolution of the wind forcing including areas close to the shoreline is the most critical component for accurate current forecasts. Additionally, it is demonstrated that wind resolution plays a large role in establishing realistic thermal and density structures in upwelling prone regions.     

Sedimentation on the cold-water coral Lophelia pertusa: cleaning efficiency from natural sediments and drill cuttings

Anthropogenic threats to cold-water coral reefs are trawling and hydrocarbon drilling, with both activities causing increased levels of suspended particles. The efficiency of Lophelia pertusa in rejecting local sediments and drill cuttings from the coral surface was evaluated and found not to differ between sediment types. Further results showed that the coral efficiently removed deposited material even after repeated exposures, indicating an efficient cleaning mechanism. In an experiment focusing on burial, fine-fraction drill cuttings were deposited on corals over time. Drill cutting covered coral area increased with repeated depositions, with accumulation mainly occurring on and adjacent to regions of the coral skeleton lacking tissue cover. Tissue was smothered and polyp mortality occurred where polyps became wholly covered by material. Burial of coral by drill cuttings to the current threshold level used in environmental risk assessment models by the offshore industry (6.3 mm) may result in damage to L. pertusa colonies.     

Elevated sedimentation on coral reefs adjacent to a beach nourishment project

An increasingly common method to restore eroding beaches is nourishment, a process by which lost sand is replaced with terrestrial or offshore sediments to widen beaches. The southeastern Florida coastline contains shore-parallel coral reef communities adjacent to eroding beaches. Scleractinian corals and other reef-associated organisms are known to demonstrate sensitivity to elevated sedimentation levels. Sediment traps were used to examine spatio-temporal sedimentation patterns and assess the effects of nourishment (dredge and fill) activities. Several environmental variables correlated with among-site spatial variability of sediment parameters. Intra-annual variability correlated with wind velocity and direction. Nourishment activities showed localized effects, with sites in close proximity to dredging areas exhibiting significantly higher collection rates and lower percent fines than control sites. A regional increase in sedimentation occurred while nourishment activities were ongoing. Due to concurrent impacts of hurricanes, only one during-construction sampling interval revealed substantially higher collection rates relative to corresponding pre-construction sampling intervals.     

Planktic foraminiferal porosity: a water mass proxy for latest Cenomanian paleoceanography, Greenhorn Sea, Western Interior USA and Canada

Planktic foraminiferal porosity analyses can be used as a water mass proxy and were conducted on samples from above the latest Cenomanian Neocardioceras or B bentonite from the Western Interior Seaway of North America. This time slice provides a snapshot of water mass characteristics in this vast epicontinental sea during the early phase of Oceanic Anoxic Event 2. Mean sample porosity decreases northward and is interpreted as northward decrease in water temperature at the depth Hedbergella delrioensis (Carsey) calcified. Four water masses are defined by porosity, their boundaries are extremely similar to water mass boundaries previously identified by others using the distributions of macrofossils, microfossils and lithology. The boundary between the Subtropical–Tropical Water Mass and Central Subtropical Water Mass was located in southern Colorado. The boundary between the Central Subtropical Water Mass and the Northern Temperate Water Mass lay at approximately 48°N latitude. This boundary is displaced northward approximately 8° latitude as compared to the Holocene planktic foraminiferal temperate ocean province. Within-sample porosity variation suggests all water masses except the Temperate Water Mass were thermally stratified. Samples from the south indicate that the Subtropical–Tropical Water Mass was the most stratified. The porosity data support a previously published data-based paleoceanographic circulation of the southwestern seaway.     

Alteration of platinum-group minerals and dispersion of platinum-group elements during progressive weathering of the Aguablanca Ni–Cu deposit, SW Spain

The distribution, mineralogy and mobility of the platinum-group elements (PGE) in the surface environment are poorly understood. This study of the lower, less altered and upper, more altered gossan, overlying the Aguablanca Ni–Cu-(PGE) magmatic deposit (Spain), has shown that the platinum-group minerals (PGM) are progressively oxidised and dispersed into iron oxides that form the gossan. A combination of the characterization of PGE in host PGM, using a scanning electron microscope, and measurement of PGE at lower concentrations in host iron oxides, using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS), has for the first time allowed the total distribution of the PGE within a gossan to be documented. This study has revealed a complete in situ alteration and dispersion sequence of the PGM including (1) breakdown of both the more stable Pt-arsenides, Pt/Pd-tellurides and the less stable bismuthotellurides, (2) formation of partially oxidised PGM, (3) development of a wide range of oxidised Pt- and Pd-bearing phases, (4) subsequent formation of Fe–PGE-oxides and PGE-hydroxides, (5) incorporation of PGE into ferruginous supergene products and lastly (6) concentration of PGE at the edges of veins and iron oxides. Dispersion of Pd is greater than for the other PGE with Pd being widely distributed throughout the iron oxides. This oxidising environment produced PGE-oxides rather than PGE-alloys, also commonly found in the surface environment, especially in placers. These results provide critical evidence for the stages of mineralogical change from PGE host mineralogy in magmatic ores to surface weathering producing PGE-oxides.