A procedure for designing natural water retention measures in new development areas under hydraulic-hydrologic invariance constraints

In recent years, in Italy and elsewhere, regional regulations based on hydraulic-hydrologic invariance (HHI) principles have taken hold, especially for new development areas. Natural water retention measures (NWRMs) are among the most interesting options to provide the storage and infiltration capacities that are needed to achieve the HHI objectives. A procedure for the design of NWRMs in new development areas under HHI constraints is presented and is based on a simple combination of Soil Conservation Service Curve Number (SCS-CN) method for determining rainfall excess and lag-time method for simulating runoff propagation. Three types of NWRMs can be considered: rain barrels, drainage wells and drainage trenches; five types of synthetic hyetographs can be selected and three different approaches for the determination of critical storm duration applied. The results obtained by applying the procedure in a new development area located in northern Italy are illustrated and some general conclusions are drawn. It clearly emerges that practitioners should pay particular attention to the correct determination of design storm duration in order to avoid large underestimations of NWRMs size. Moreover, different combinations of the three NWRMs can provide the required reduction of peak of runoff after the transformation, but it appears that drainage trenches are more effective with respect to harvesting systems in reducing the peak runoff value

Root reinforcement dynamics in subalpine spruce forests following timber harvest: A case study in Canton Schwyz, Switzerland

Root reinforcement is a key factor when dealing with slope stability problems and is an important quantitative criterion for the evaluation of the protective function of forests against shallow landslides, as well as for the adoption of appropriate practices in protection forest management. Although many models have been developed to estimate root reinforcement, a reliable quantification that considers both its spatial and temporal variability still remains a challenge. This work aims to extend the understanding of the long term spatial and temporal dynamics of root reinforcement after forest harvest in subalpine spruce forests by supplying new experimental data and applying a state-of-the-art model.We estimated root reinforcement decay 5, 10 and 15 years after timber had been harvested in spruce stands in a small catchment in the Swiss Alps. We collected root distribution data at different distances from the trees and calibrated and validated a root distribution model (RootDis). To estimate root mechanical properties, we tested roots up to 12 mm diameter in the field, and computed root reinforcement for each case study with the Root Bundle Model. Finally, we developed a new model for the estimation of root reinforcement decay, based on the observed change in root distribution after felling and on the decay of the root pullout force. The final result is a model for the spatial-temporal prediction of root reinforcement heterogeneity and dynamics in subalpine spruce forest stands. Five year old harvested spruce forest in the climatic conditions of the study area provides 40% of the root reinforcement of live forest, while 15 years old harvested forest provides no reinforcement at all. Shrub species and natural regeneration could guarantee almost the 30% of the root reinforcement of a live forest after 15 years from cutting. Additional work is now required to further validate the model and implement these results in a slope stability analysis

Water balance of rice plots under three different cultivation methods : First season results

In the last years rice cultivation methods have been the object of an intense research activity aiming to implement new irrigation methods in addition to traditional flooding, in order to reduce water use. This change has concerned also the traditional paddy-rice territories of the north-west of Italy, where rice has been traditionally cultivated as flooded and where paddy fields are a strong landscape landmark and represent a central feature in the Italian and European network for nature protection. The new techniques introduced in these territories consist in a dry seeding followed by field flooding after about one month (third-fourth leaf), and in a full aerobic cultivation with intermittent irrigations, similarly to standard irrigated crops. This paper presents the results obtained after the first year of a monitoring activity carried out at the Ente Nazionale Risi Experimental Station of Castello d\u2019Agogna-Mortara (PV, Italy), where the main terms of water balance have been measured or estimated during the whole crop season. Because there is a substantial lack of data concerning the water balance related to the new water management techniques, the data are of wide interest despite this study covered only one season. The results here presented show that dry seeding-delayed flooding method required a rather similar amount of water respect to the traditional flooding method (2200 mm and 2491 mm, respectively), whereas the aerobic technique required one order of magnitude less water (298 mm), also due to the very shallow depth of the surface aquifer. Since evapotranspiration was nearly the same for the three methods (578 mm, 555 mm, and 464 mm, respectively for traditional flooded, dry seeding-delayed flooding and aerobic methods), percolation was very high in the case of the two flooded methods and very limited in the case of the aerobic cultivation with intermittent irrigations. These results suggest that, if the aerobic cultivation of rice represents a highly effective water-saving technique at the field scale, at the same time if applied on a large scale in traditional paddy areas, as the north-west of Italy, it could be a potential threat for groundwater dynamics, due to the dramatic decrease of groundwater recharge, and in general for traditional landscape conservation and nature protection

A Customized GIS-based Model for Stormwater Mitigation by LID Controls

The effects of urbanization on hydrology, water quality, habitats, as well as ecological and environmental compartments, represent issues of primary importance for multiple agencies at the national, regional and local levels. In the context of the SMART-GREEN project, funded by Fondazione Cariplo and currently in progress, a new tool called SMARTGREEN plugin is under development in a desktop GIS framework. The software will provide: 1) a user friendly interface to help analysts in the hydrologic-hydraulic modelling of urban watersheds and drainage networks through the model MOBIDIC-U, with the possibility of considering Low Impact Development (LID) solutions, 2) a set of tools to easily import information from existing databases, 3) a set of tools to check the database quality, highlight missing or incorrect data, and suggest possible fixes automatically, 4) an easy and faster way to speed up the analysis of the results. In this work, we show the main functionalities of the plugin through a basic test case. The software aims at supporting water service management companies in planning LID implementation in urban areas

A tailored green-approach for managing CSOS in high density urban areas

This study was aimed at providing evidence about the possibility to adopt low-cost \u201cgreen-approaches\u201d for mitigating peak flow, volume and pollution loads of CSO in areas where high density of urbanization occur. In particular, the proposed approach exploits detention, infiltration and self-depuration capacities of natural systems already existing in peri-urban areas, in order to achieve a tailored solution that is suited to the specific context. The findings presented in this work show that combining first-flush tank (FFT) with a constructed wetland system (CW) and finally managing the flows in the receiving water body (RWB) about 90% of pollutant load abatement can be achieved. Therefore, the system can be simultaneously designed to pursue flood risk reduction (abatement of flow peak) and improvement of receiving water quality objectives. Moreover, each component of the proposed system has some peculiarities. For example, CW performs a dual function, i.e. on one hand it cuts the peak of flow thanks to its storage capacity, while on the other hand it reduces the volume thanks to its infiltration capacity. This features are most important especially in the context of \u201chydraulic-hydrologic\u201d invariance measures (that are becoming more and more present at local scale) where the reduction of peak discharge has necessarily to be accompanied by a reduction of volumes. Further improvements can be obtained through the control of flow in the RWB aimed to maintaining a correct ratio between upstream accumulation and downstream flow control according (i) the variability of flow in input to the RWB and (ii) the downstream canal hydraulic capacity. Flow control can be achieved by installing smart gates that operate automatically based on flow sensors and software-based actuators. Finally, the additional ecosystem services that can be provided by the green components of the system combined with the relatively low-cost of the interventions make the approach particularly attractive for small municipalities where large investments are seldom possible

Exploring the performances of a new integrated approach of grey, green and blue infrastructures for combined sewer overflows remediation in high-density urban areas

Most sewage collection systems designed between 19th and early to mid-20th century use single-pipe systems that collect both sewage and urban runoff from streets, roofs and other impervious surfaces. This type of collection system is referred to as a combined sewer system. During storms, the flow capacity of the sewers may be exceeded and the overflow discharged into a receiving water body (RWB) through spillways without any control and remediation. Combined sewer overflows (CSOs) may, therefore, produce serious water pollution and flooding problems in downstream RWBs. Methodologies for a rational management of CSOs quantity and quality share many commonalities, and these two aspects should be considered together in order to maximize benefits and promote local distributed actions, especially in high urban density areas where the space availability for the construction of CSO storage tanks is often a limiting factor. In this paper, a novel strategy to control downstream flow propagation of a CSO as well as to improve its quality is tested on a real case study in the area of the metropolitan city of Milan. The approach is based on the combination of grey, green and blue infrastructures and exploits the integrated storage and self-depuration capacities of a first-flush tank, a constructed wetland and a natural stream to obtain admissible flow rates and adequate water quality in the RWB. The results, evaluated through a modelling framework based on simplified equations of water and pollutants dynamics, show excellent performances for the integrated system, both in terms of flow control and pollution mitigation. The pollution, using biological oxygen demand concentration as a proxy of the whole load, was decreased by more than 90% and downstream flooding situations were avoided, despite the spillway was not regulated. Concerning the economic point of view, from a rough estimate of the costs, the system allows reducing the investment of 30 to 50% in respect to the traditional CSO controls based solely on flow detention tanks. The proposed approach, as well as the modelling framework for its effective implementation, appear strongly scalable in different world contexts and aim to fill the gap between urban and rural environments in the management of stormwater and CSOs, promoting the involvement of the water managers, the irrigation-reclamation agencies and regional authorities

Exploring scale-effects on water balance components and water use efficiency of toposequence rice fields in Northern Italy

Water use efficiencies (WUEs) between 20% and 60% are commonly reported for single rice paddies. When larger spatial domains are considered, higher WUE than minimum values observed for individual fields are expected due to water reuse. This study investigates scale-effects on water balances and WUEs of four adjacent rice fields located in Northern Italy and characterized by different elevations (A 45 B + C > D). Water balance terms for the paddies were quantified during the agricultural season 2015 through the integrated use of observational data and modelling procedures. Following a Darcy-based approach, percolation was distinguished from net seepage. Results showed net irrigation of about 2,700 and 2,050 mm for fields A and B, and around 640 and nearly 0 mm for C and D. WUE of A, B, C and D amounted, respectively, to 21, 28, 66 and >100%. Values for C and D were due to less permeable soils, to seepage fluxes providing extra water inputs and to the shallow groundwater level. When the group of paddies ACD was considered (B was not included since it was separated by a deep channel), net irrigation and WUE were found to reach 1,550 mm and 39%, confirming the important role of water reuses in paddy agro-ecosystems

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Calibration of distributed shallow landslide models in forested landscapes

In mountainous-forested soil mantled landscapes all around the world, rainfall-induced shallow landslides are one of the most common hydro-geomorphic hazards, which frequently impact the environment and human lives and properties. In order to produce shallow landslide susceptibility maps, several models have been proposed in the last decade, combining simplified steady state topography- based hydrological models with the infinite slope scheme, in a GIS framework. In the present paper, two of the still open issues are investigated: the assessment of the validity of slope stability models and the inclusion of root cohesion values. In such a perspective the \u201cStability INdex MAPping\u201d has been applied to a small forested pre-Alpine catchment, adopting different calibrating approaches and target indexes. The Single and the Multiple Calibration Regions modality and three quantitative target indexes \u2013 the common Success Rate (SR), the Modified Success Rate (MSR), and a Weighted Modified Success Rate (WMSR) herein introduced \u2013 are considered. The results obtained show that the target index can 34 003_Bischetti(569)_23 1-12-2010 9:48 Pagina 34 significantly affect the values of a model\u2019s parameters and lead to different proportions of stable/unstable areas, both for the Single and the Multiple Calibration Regions approach. The use of SR as the target index leads to an over-prediction of the unstable areas, whereas the use of MSR and WMSR, seems to allow a better discrimination between stable and unstable areas. The Multiple Calibration Regions approach should be preferred, using information on space distribution of vegetation to define the Regions. The use of field-based estimation of root cohesion and sliding depth allows the implementation of slope stability models (SINMAP in our case) also without the data needed for calibration. To maximize the inclusion of such parameters into SINMAP, however, the assumption of a uniform distribution of probability of the parameters must be overtaken. In small and steep catchments where there is an intrinsic susceptibility to instability phenomena, moreover, an additional class of low probability of instability (0.81)<1.0) has been proposed to better discriminate the areas classified as unstable