Streamflow and weather conditions of seven small coastal watersheds, British Columbia, Canada, 2013–2019

Hydrometeorological observations of small watersheds of the northeast Pacific coastal temperate rainforest (NPCTR) of North America are important to understand land to ocean ecological connections and to provide the scientific basis for regional environmental management decisions. The Hakai Institute operates a densely networked and long-term hydrometeorological monitoring observatory, that fills a spatial data gap in the remote and sparsely gauged outer coast of the NPCTR. Here we present the first five water years (October 2013–October 2019) of hourly streamflow and weather data from seven small (< 13 km2), coastal watersheds. Average yearly rainfall was 3267 mm, resulting in 2317 mm of runoff and 0.1087 km3 of freshwater exports from all seven watersheds per year. However, rainfall and runoff were highly variable depending on location and elevation. The seven watersheds have rainfall-dominated (pluvial) streamflow regimes, streamflow responses are rapid and most water exports are driven by high-intensity fall and winter storm events. Measuring rainfall and streamflow in remote and topographically complex rainforest environments is challenging, hence advanced and novel automated measurement methods were used. These methods, specifically for stream flow measurement allowed us to quantify uncertainty and identify key sources of error, which varied by gauging location. Links to the complete dataset, watershed delineations with metrics, and calculation scripts can be found in Sect. 6 and 7.

B-flood 1.0: an open-source Saint-Venant model for flash-flood simulation using adaptive refinement

The French Riviera is very often threatened by flash floods. These hydro-meteorological events, which are fast and violent, have catastrophic consequences on life and property. The development of forecasting tools may help to limit the impacts of these extreme events. Our purpose here is to demonstrate the possibility of using b-flood (a subset of the Basilisk library http://basilisk.fr/, last access: 8 November 2021), which is a 2D tool based on the shallow-water equations and adaptive mesh refinement. The code is first validated using analytical test cases describing different flow regimes. It is then applied to the Toce river valley physical model produced by ENEL-HYDRO in the framework of the CADAM project and on a flash-flood case over the urbanized Toce area produced during the IMPACT project. Finally, b-flood is applied to the flash flood of October 2015 in Cannes in south-eastern France, which demonstrates the feasibility of using software based on the shallow-water equations and mesh refinement for flash-flood simulation in small watersheds (less than 100 km2) and on a predictive computational timescale.

How Extreme Were The Torrential Floods In Smaller Watersheds In Serbia In September 2014

The September torrential floods in 2014 in the Eastern Serbia were a real disaster for local residents in municipalities of Kladovo, Negotin and Majdanpek. Meteorological extreme event caused the hydrological extreme event which led to declaration of the emergency situation in all three municipalities. The combined method of Soil Conservation Service and synthetic unit triangular hydrograph (SCS-SUH) is employed to compute the maximal discharges in small watersheds of Dupljanska reka and Manastiricki potok, in order to assess the extremeness of September 2014 torrential flood events. Since the surface runoff is accompanied by intensive soil erosion on watershed slopes and the maximal discharges by sediment transport in river beds, estimation of mean annual sediment transport is also presented in this work. The September 2014 floods will remain historic given that they took 5 human lives and caused enormous material damage for local municipalities, so presented hydrological analysis should be taken as very important part of flood event documentation along with reports of municipalities’ emergency headquarters.

Aquatic Biological Diversity Responses to Flood Disturbance and Forest Management in Small, Forested Watersheds

We examined riparian system responses to an extreme rainfall event on 1–4 December 2007, in eleven small watersheds (mean area—13.2 km2) from 2008–2016 at debris flow, high flood, and low flood reaches (all extended overbank flows). Macroinvertebrate responses followed expected outcomes after extreme disturbance including increasing chironomids and other multi-voltine species. A core assemblage of twenty abundant and common species-maintained populations even after debris flow (likely by recolonizing quickly) with total richness during project of 253 including 183 rare species (<0.01 total abundance) supporting an annual turnover of species from 22 to 33%. Primary disturbance changes to habitat were declines in shade and in-channel wood at all reaches, more strongly at debris flow reaches. Macroinvertebrate communities across disturbance intensities became increasingly similar after the storm. Combined effects of the flood reducing channel complexity and previous logging decreasing in-channel wood recruitment from riparian systems, limits habitat complexity. Until this feature of forested watershed streams returns, there appears to be a ceiling on reach scale aquatic biological diversity.

Aufeis in the mountainous areas of the northwestern part of the Selenga River basin

The article presents the results of research on aufeis (icings) in the area where their concentration is maximal for the Selenga River basin. Landsat and Sentinel satellite imagery data were used to map the current location of aufeis in the valleys of permanent watercourses of the transboundary Dzhida River basin. It was found out that up to 3.5 thousand small aufeis with the area from 0.005 to 1 km2 are formed in small watersheds of the territory. The total area of aufeis within the considered territory can reach up to 92.1 km2, the aufeis coverage is 0.45%. It is revealed that in the total amount, small aufeis prevail, the area of which lies within 0.01 to 0.1 km2. In addition, ecosystem and economic aspects of the processes of ice formation on the territory of Russia and neighbouring Mongolia are considered.

Macroinvertebrates responses based on chemical and physical variables in urban streams

The Land uses and occupations around small watersheds generate negative impacts such as deterioration of water quality, environmental simplification, reduced availability of habitats for species, and loss of biodiversity. Benthic macroinvertebrates are an important aquatic community and are widely used in environmental monitoring actions in aquatic ecosystems, including urban streams, which are still little studied in Brazil. In our study, an urban headwater basin (Monjolinho River Basin) was studied on the benthic community structure, together with the physical and chemical variables of the water, as an environmental monitoring tool calculated by RHDEP, TSI, BMWP indexes and abundance-biomass curves. The results showed a gradient of environmental quality, where the best environments are a consequence of preserving the vegetation cover. These environments (Espraiado and Canchim) present groups sensitive to environmental degradation (Ephemeroptera, Plecoptera and Trichoptera), greater diversity and a better structure in the respective benthic macroinvertebrate assemblages. Among the streams sampled, one is very clean, four are moderately polluted, and one is severely polluted. Thus, considering that these streams’ waters are essential for public supply, actions to clean up and recover degraded environments are urgent and a priority.

Establishment of the minimum data set for cultivated-layer quality assessment and its verification: A case study of sloping farmland in a purple hilly area, China

Sloping farmland is an important cultivated land resource and erosion source. Cultivated-layer quality directly affects the soil productivity and erosion resistance of sloping farmland. We aim to select the most effective soil property index to construct a minimum data set (MDS) and use two methods (the weighted additive cultivated-layer quality index (CLQIW) and Nemoro cultivated-layer quality index (CLQIN)) to accurately evaluate the cultivated-layer quality of sloping farmland in purple hilly areas. The total data set (TDS) of 12 soil indexes was screened by principal component analysis (PCA) and correlation analysis, and a MDS was constructed to assess the CLQIW and CLQIN. The results showed that (1) the cultivated-layer soil quality of the MDS comprises cultivated-layer thickness, soil bulk density, saturated hydraulic conductivity, sand, clay, shear strength and soil organic matter. The MDS can accurately reflect the effective soil information (RW2=0.7524, RN2=0.8059) and can replace the TDS in cultivated-layer evaluation. (2) CLQIN-MDS has a higher Ef and lower ER than CLQIW-MDS does, so CLQIN-MDS is better for evaluating the cultivated-layer quality of purple soil of sloping farmland. (3) For the two evaluation methods, the quality classifications of the two small watersheds have similar trends, with most plots in grades II~III (approximately 90%). (4) The main obstacles of the two small watersheds are poor nutrients and low soil shear strength, which can be reasonably controlled by subsoiling combined with biochar. These results can facilitate the construction of reasonable cultivated-layers and improvements in the cultivated-layer soil quality of sloping farmland.