Drone-based assessment of microsite-scale hydrological processes promoted by restoration actions in early post-mining ecological restoration stages

A successful choice of post-mining restoration activities in dry climates may depend on relevant features related to topographic characteristics, hydrological processes and vegetation development, which will determine functional recovery in these ecosystems. The combination of different restoration techniques to reestablish vegetation, such as sowing and plantation, implies the interspersion of bare-soil areas with vegetated areas in early plant development stages, which may result in an associated mosaic of hydrologic functioning. In this study, we conducted a drone-based assessment to disentangle the role played by microsite-scale hydrological processes (i.e., planting hole slope, sink volume capacity, individual catchment area, Flow Length Index) promoted by restoration actions in soil protection and vegetation development on the hillside scale. Based on two contrasting restoration scenarios (Steep hillside and Smooth hillside), the different applied restoration treatments conditioned the microtopographic processes on the planting hole scale and, therefore, resource redistribution. The main results showed higher planting hole functionality on the smooth hillsides than on steep hillside, which resulted in greater water availability and bigger vegetation patches. By addressing the role of hydrological processes on the microsite scale, our study contributes substantially to prior knowledge on the relevant factors for ecosystem development and post-mining restoration success. It also demonstrates that high-resolution drone images can be a very useful tool for monitoring restoration actions, especially in large, inaccessible and unstable restored areas.The study was funded by the LIFE TECMINE Project (LIFE16 ENV/ES/000159) from the European Programme for the Environment and Climate Action (2014–2020)*. L.M. was supported by the Spanish MICINN (PTA2019-018094). The CEAM foundation is funded by the Generalitat Valenciana

Innovative Techniques for Landscape Recovery after Clay Mining under Mediterranean Conditions

Open-pit mining results in profound modifications at different environmental scales that may persist for very long time periods, or even indefinitely. Considerable research efforts in mine reclamation strategies have been made, although reclamation failures are still common. In dry climates, such as in the Mediterranean Basin, successful actions may depend on features related to proper species selection and restoration techniques, which may substantially contribute to provide substrate stability and facilitate the regeneration of the main ecological processes. In this context, we developed the TECMINE case-study aimed to evaluate the feasibility and suitability of innovative restoration practices applied to clay-mine reclamation under Mediterranean conditions. The restoration strategy was designed at the landscape level with two main approaches: the recovery of natural geomorphology shapes and ecological restoration, including vegetation recovery and soil quality, based on proper reference ecosystems. After the geomorphological land remodeling, a combination of several innovative restoration techniques was implemented to reclaim plant communities and ecosystem functioning. These techniques involved: (i) accurate species selection according to microhabitat characteristics; (ii) high-quality plant production; (iii) surface remodeling to improve substrate stabilization; and (iv) implementing rainfall collection to enhance resources availability, soil fertility improvement and the amelioration of abiotic conditions for seedlings. Finally, we developed a monitoring program to assess the success of the implemented restoration techniques over time. The application of these innovative techniques has reported interesting results and represents a step forward in the improvement of mine restoration under Mediterranean climate.The study was funded by the LIFE TECMINE Project (LIFE16 ENV/ES/000159) from the European Programme for the Environment and Climate Action (2014–2020)*. L.M. was supported by the Spanish MICINN (PTA2019-018094). The CEAM foundation is funded by the Generalitat Valenciana

Framework for remediation of rivers impacted by legacy metal mine pollution

Seven percent of surface waters in England and Wales are impacted by pollution from abandoned non-ferrous metal mines. It is estimated that there are about five thousand five hundred of these. There is no legal liability to any party attached to abandoned metal mines in the UK if they ceased operation before 1999. Preventing pollution from entering river catchments from these sources can be expensive and public funds are limited in extent. These enduring sources of pollution are a significant impediment to compliance with the legislative requirements, such as the European Water Framework Directive. This thesis develops a framework for integrating pre-existing tools and methodologies to address this environmental problem: Environmental Impact Assessment (EIA), Life Cycle Impact Assessment (LCIA) and Payments for Ecosystem Services (PES). By fully quantifying the economic, social and environmental impacts of abandoned mine discharges and the net benefits of potential management interventions over different scales, it is proposed that the framework can provide a sustainable way forward for identifying appropriate cost-effective remedial interventions, identify sources of funding for remediation to take place through PES, while at the same time being sensitive to stakeholder concerns. To determine the effectiveness of this framework two phases of research have been undertaken. The first was a series of interviews with a range of key stakeholders with relevant knowledge and expertise, targeting key concerns and conflicts that arise in managing legacy pollution. The second was to apply the framework to a specific mine-impacted catchment to determine the effectiveness of the framework and an optimal solution for that site. Key findings of stakeholder interviews revealed the general positive attitude towards PES-schemes also discrepancies in knowledge between different sectors. Industrial representatives emphasised the likely need for regulation to initiate such processes. The potentially important role of stewardship and conservation organisations as “ethical brokers” for such schemes was highlighted, given their expertise at communicating and managing a range of stakeholder opinions. The application of the framework to the Hebden Beck catchment in North Yorkshire found that multiple small scale passive remediation at affected locations would be an optimal solution. The full costs of such systems are outweighed by the potential ecosystem service benefits of metal removal from upland streams. Fundamental to the acceptability and sustainability of the remedial solution was the requirement for habitat offsetting to be incorporated into the proposed works

Sediment budget for a North Pennine upland reservoir catchment, UK

Sediment delivery from upland fluvial systems in the UK is of considerable importance in catchment management. However, scarcity of detailed data on sediment sources, storage and linkages between geomorphic processes inhibits current understanding of such systems. A sediment budget for an un-gauged, upland catchment at Burnhope Reservoir (North Pennines, UK) has been developed that couples catchment sediment sources and suspended sediment dynamics to reservoir sedimentation and; quantifies historic and contemporary sediment yields. Stream-side scars and cut banks are the dominant catchment sediment sources with greatest connectivity in first order tributaries during high discharge events. The catchment sediment system is supply-limited and sediment exhaustion occurs on an intra and inter-storm event basis. Bathymetric surveys, core transects and aerial photographs were used to assess spatial variability in sediment accumulation in the reservoir. Physical and radiometric analysis ((^137)Cs) of core sediments provided estimates of dry bulk density, particle size variations and a sedimentation chronology. Total reservoir sedimentation over the 67 year period has been estimated at 592 t yr(^1) ± 10% (33.3 t km(^-2) yr(^1)) with average sedimentation rates of 1.24 and 0.77cm yr(^-1)calculated from the distal and proximal areas of the reservoir respectively. Inputs of fine suspended sediment from direct catchwater streams accounts for 54% of sediment supply to the reservoir (best estimate yield of 318 t yr(^-1) ± 129%), while inputs from the actively eroding reservoir slopes and shorelines contribute a gross yield of 328 t yr(^-1) + 92%. However, 70% of sediment from shoreline erosion is >2 mm diameter and is stored on the shoreline and toe slopes. The remaining 30% (98.41) of fine sediment is transferred to deep-water reservoir storage. This highlights the importance of shoreline erosion and sediment storage in the overall budget. Error analysis of the sediment balance equation enabled the residual sediment inputs from ungauged tributary streams to be estimated (232.6 t yr(^-1) ± 394.9%). The specific sediment yield of 33.3 t km(^-2) yr(^-1) to Burnhope Reservoir is relatively low. It is 40% lower than the average yield of 84 t km(^-2) yr(^-1) estimated from British storage reservoirs (DETR, 2001) and an order of magnitude lower than estimates from South Pennine reservoirs. Analysis of the particle size of core sediments showed abrupt increases in sand-sized particles in the top 20 cm of the cores (late 1970s onwards). This is related to the diverging trends in winter and summer-centred rainfall records and rapidly fluctuating reservoir levels. The sediment budget approach together with the chronology of reservoir sedimentation identifies the main sediment transfer pathways in the Burnhope catchment, and provides evidence of both extrinsic and intrinsic controls on sediment transfer and deposition

Anàlisi mitjançant modelització integrada hidràulic-hidrològica de l’estabilitat de solucions de restauració geomorfològica dissenyades amb el mètode GeoFluv

Les restauracions geomorfològiques són una tècnica força nova per a la restauració de mines a cel obert, amb un objectiu molt clar d’estabilitat davant l’erosió a llarg termini. Resulta de gran interès combinar l’ús de mètodes i softwares usats per generar dissenys de restauracions d’aquest tipus, com podria ser el Geofluv – Natural Regrade, amb models d’erosió del sòl que ajudarien a assegurar que les solucions dissenyades són estables a llarg termini. En aquest treball s’estudia la possibilitat de fer servir el model numèric Iber com a complement de Geofluv-Natural Regrade en el disseny de restauracions de mines. Per fer-ho, s’han simulat un total de tres pluges de disseny (de 2, 5 i 100 anys) per veure les tendències erosives d’una restauració feta a la mina del Machorro, al Parc Natural de l’Alto Tajo, i s’han comparat amb les erosions reals de la zona esmentada, calculades a partir de la diferència dels models d’elevació del terreny dels anys 2012 a 2018. Els mapes d’erosió obtinguts per a les tres pluges mostren una bona aproximació a la realitat del canal principal: les màximes erosions es donen en el seu tram final i a una part del tram central. En canvi, els canals secundaris on l’erosió és menor es troben millor representats amb la pluja de menor període de retorn. Tot i que caldrien estudis més complexos, d’aquesta primera aproximació fet amb Iber es pot concloure que aquest mostra un gran potencial a l’hora d’usar-se com a complement per al disseny de restauracions geomorfològiques.Las restauraciones geomorfológicas son una técnica bastante novedosa para la restauración de minas a cielo abierto, con un objetivo muy claro de estabilidad ante la erosión a largo plazo. Resulta de gran interés combinar el uso de métodos y software usados para generar diseños de restauraciones de este tipo, como podría ser el Geofluv – Natural Regrade, con modelos de erosión del suelo que ayudarían a asegurar que las soluciones diseñadas son estables en largo plazo. En este trabajo se estudia la posibilidad de utilizar el modelo numérico Iber como complemento de Geofluv-Natural Regrade en el diseño de restauraciones de minas. Para ello, se han simulado un total de tres lluvias de diseño (de 2, 5 y 100 años) para ver las tendencias erosivas de una restauración hecha en la mina del Machorro, en el Parque Natural del Alto Tajo, y se han comparado con las erosiones reales de dicha zona, calculadas a partir de la diferencia de los modelos de elevación del terreno de los años 2012 a 2018. Los mapas de erosión obtenidos para las tres lluvias muestran una buena aproximación a la realidad del canal principal: las máximas erosiones se dan en su tramo final y en una parte del tramo central. En cambio, los canales secundarios donde la erosión es menor se encuentran mejor representados con la lluvia de menor período de retorno. Aunque se necesitarían estudios más complejos, de esta primera aproximación realizada con Iber se puede concluir que éste muestra un gran potencial a la hora de usarse como complemento para el diseño de restauraciones geomorfológicas.Geomorphic reclamation is a very new technique for the restoration of open-cut mines, with a very clear objective of long-term stabilisation against erosion. It is of great interest to combine the use of methods and software used to generate restoration designs of this type, such as Geofluv - Natural Regrade, with soil erosion models that would help to ensure that the solutions designed are long-term stable. This final work studies the possibility of using the Iber numerical model as a complement to Geofluv-Natural Regrade in the design of mine reclamation. To do so, a total of three design rains (of 2, 5 and 100 years of return period) have been simulated to see the erosion trends of a restoration carried out in the Machorro mine, in the Alto Tajo Natural Park, and compared with the real erosion of the area, calculated from the difference in the elevation models of the land from 2012 to 2018. The erosion maps obtained for the three cases show a good approximation to the reality of the main channel: the maximum erosion occurs in the final section and in part of the central section. In contrast, the secondary channels where erosion is less severe are better represented with the lightest rain. Although more complex studies are needed, it can be concluded from this first approximation made with Iber that it shows great potential for use as a complement to the design of geomorphological restorations

Towards effective conservation of the Pilbara Early Life Sites as a multifunctional landscape: exploring lessons from national and international baest practice

Geoconservation - the practice of conserving geological features, from the landscape scale all the way down to the individual crystal scale - is growing in importance, as sites of international heritage value around the world face increasing pressure from human activities. A collection of geological sites that urgently require more effective protection is in the Pilbara region of Western Australia, where ancient rocks - up to 3.5 billion years old - that are extremely well preserved contain fossil stromatolites and microfossils that represent the earliest convincing evidence of life on Earth (henceforth Pilbara Early Life Sites). In addition, the Pilbara Early Life Sites contain some of the best evidence of the environments where life gained a foothold on early Earth, and even provide clues as to how life may have begun. Indeed, these sites help to paint a picture of the early Earth, when small volcanic islands rising out from the ocean formed the first exposed landmasses and provided heat, minerals, and chemical energy for primitive life to form and grow into communities that spread across shallow pools on land, occupied hydrothermal veins, and adapted to shallow marine habitats. This information is key not only for understanding the origin and evolution of life on Earth, but to help develop strategies for where to search for life on Mars and elsewhere in the solar system and is used by space agencies from around the world in mission planning. The excellent preservation of the Pilbara Early Life Sites is globally extremely rare. Such excellent preservation is key to understanding the processes of past life, and therefore using these sites as a teaching resource. The Pilbara Early Life Sites are small, isolated outcrops and are therefore vulnerable to irretrievable loss through illegal sample collection from unknown sources. Ever since the Pilbara Early Life Sites were first described by Walter et al. (1980) and by Lowe (1980), illegal collection of valuable outcrop material has been an issue of real concern. Because the key sites where excellent preservation of textures and the relationships between the traces of life and their habitats are so small (10m2) and isolated, and because the value of sites is critically dependent on being able to view the fossils in-situ, within their relevant context where their relationship to surrounding geology can be viewed, the illegal removal of material is a major loss of both important scientific knowledge and universal heritage value. There have been several attempts to conserve the Pilbara Early Life Sites, however none of these have succeeded in the long term. This thesis investigates whether the current method of protection is adequate, identifies and evaluates a range of approaches for conservation moving forward, and develops a roadmap toward more effective, meaningful conservation of the Pilbara Early Life Sites. This roadmap strives to ensure the conservation and management of the Pilbara Early Life Sites does not negatively impact local industries, communities, and future scientific research. Rather, this roadmap will facilitate an enhanced public understanding of the sites, allow for education of future researchers, conservation practitioners, and the public, as well as promote responsible scientific research through better working partnerships with other stakeholders. This thesis has employed a mixed-methods approach, wherein qualitative data was collected, and both qualitative and quantitative analysis techniques were used. These collection and analysis techniques included interviews, literature review, PESTLE analysis, SWOT analysis, and application of the Brocx and Semeniuk ‘Geoheritage Toolkit’. The analyses show that the current method of conservation is inadequate, and that alternative methods of conservation and management strategies are required to ensure the future protection of the Pilbara Early Life Sites. These will be informed by best national and international practice. The recommend protection is National Heritage Listing. Due to the extended timeframe and practical considerations of implementing National Heritage Listing, additional conservation measures are also explored

Aquatic Habitat Characterization and Use in Groundwater Verses Surface Runoff Influenced Streams: Brown Trout (Salmo Truttal) and Bullhead (Cottus Gobio)

Riverine physical habitats and habitat utilization by fish have often been studied independently. Varying flows modify habitat composition and connectivity within a stream but its influence on habitat use is not well understood. This study examined brown trout (Salmo trutta) and bullhead (Cottus gobio) utilization of physical habitats that vary with flow in terms of size and type, persistence or uration, and frequency of change from one state to another, by comparing groundwater-dominated sites on the River Tern (Shropshire)with surface runoff-dominated lowland, riffle-pool sites on the Dowles Brook (Worcestershire). Mesohabitat surveys carried out at two-month intervals on a groundwater-dominated stream and on a surface runoff-influenced stream showed differences in habitat composition and diversity between the two types of rivers. The temporal variability in mesohabitat composition was also shown to differ between the two flow regime types. In the groundwater-influenced stream, mesohabitat composition hardly varied between flows whereas in the flashy stream it varied to a great extent with discharge. Habitat suitability curves for brown trout and bullhead were constructed to predict the potential location of the fish according to flow. The resulting prediction maps were tested in the field during fish surveys using direct underwater observation (snorkelling). Under the groundwater-influenced flow regime brown trout displayed a constant pattern of mesohabitat use over flows. Mesohabitats with non-varying characteristics over flows and with permanent features such as large woody debris, macrophytes or any feature providing shelter and food were favoured. Biological processes, such as hierarchy, life cycle and life stage appeared to play a key role in determining fish habitat use and to a greater extent than physical processes in these streams. Bullhead observations in the flashy river showed that mesohabitat use varied with flow but that some mesohabitats were always favoured in the stream. Pools and glides were the most commonly used mesohabitat, due to their stability over flows and their role as shelter from harsh hydraulic conditions and as food retention zones. The presence of cobbles was also found to be determinant in bullhead choice of habitat. In this flashy environment, physical processes such as flow and depth and velocity conditions appeared to be a more decisive factor in bullhead strategy of habitat use than biological processes. This research shows that: 1. Though differences in habitat use strategies between the two flow regimes can in part be attributed to differing ecology between the species, flow variability affects fish behaviour. 2. A stable flow regime allows biological processes to be the main driving force in determining fish behaviour and location. A highly variable environment requires fish to develop behaviour strategies in response to variations in hydraulic conditions, such as depth and velocity, which constitute the key factor in determining fish location. _____________________________________________

Geomorphic design and modelling at catchment scale for best mine rehabilitation – The Drayton mine example (New South Wales, Australia)

Computer modelling and design tools can assist in environmental management. In particular, post-mining landscapes with large volumes of materials require shaping for optimal erosional stability and ecological and visual integration into the surrounding undisturbed landscape. This paper evaluates the complementary capabilities of landscape evolution modelling (SIBERIA) and geomorphic design software (Natural Regrade with GeoFluv). An existing 11.5-ha waste rock dump (Hunter Valley, New South Wales, Australia) served as the study site. The SIBERIA modelling demonstrated that geomorphic design reduced erosion by half that of conventional designs while being able to store an extra 7% of mine waste volume. Additionally, the spatial pattern of gullying was able to be predicted by modelling, which allowed management in subsequent geomorphic design, and successively more stable patterns. In conclusion, the joint use of the Natural Regrade with GeoFluv geomorphic design software with the SIBERIA landscape evolution model showed complementary capabilities for enhancing mine rehabilitation.This paper is the outcome of a joint research of the three authors, made possible by means of a research stay of J.F. Martín Duque, hosted by G.R. Hancock and G.R. Willgoose, at the University of Newcastle (UoN, Australia). This stay has been funded within a program Estancias de Movilidad de Profesores e Investigadores en Centros Extranjeros de Enseñanza Superior of the Spanish Minister of Education, Culture and Sports (reference PRX16/00441). The authors acknowledge the kind collaboration of the Tom Farrell Institute for the Environment of the UoN. Drayton (AngloAmerican) has kindly supported this research, by providing the GeoFluv-as-built topography, along with all the needed information, which main aim has been getting knowledge in order to develop best mine rehabilitation practises. The assistance of Matt Lord and team is highly appreciated. This manuscript is also a contribution under the joint research of the Ecological Restoration Network REMEDINAL-3 of the Madrid Community (S2013/MAE-2719).Peer reviewe