Small Mountainous Catchment Research Articles

The impact of Wallachian settlement on relief and alluvia composition in small valleys of the Carpathian Mts. (Czech Republic)

The impact of the Wallachian settlement on small mountain catchments has been studied at the example of Škorňanský and Hartisov Streams (Moravskoslezské Beskydy Mts, Western Outer Carpathians). Between the 16th and the 19th centuries the Wallachian people introduced pastoral management originating from the woodless Balkans to the forested mid-altitude mountain area under study. This area was subjected to rapid settlement, intense grazing in forests and slash-and-burn deforestation. To assess the geomorphic effects of Wallachian activity in the catchments studied, grain size, structure, organic matter content, and the plant macrofossil composition of the alluvia forming terrace levels in the mouths of the Škorňanský and Hartisov Streams were analysed. Radiocarbon dating, 137Cs and 210Pb analyses and dendrochronological dating were also applied to determine the age of the alluvia studied. The results were compared with land-use and land-cover changes recorded on archival maps and pictures, and with population changes in the study area. It was found that the two successive trends of catchment settlement and later depopulation have led to the development of inset terraces on the outlet fans of the Škorňanský and Hartisov Streams. In the study catchments both settlement/deforestation and depopulation/land abandonment occurred very rapidly which also caused abrupt geomorphic changes. Before human disturbance, fluvial erosion and the redeposition of older Pleistocene deposits predominated. As a result coarse, gravel alluvia were deposited within stream channels. The stage of massive overbank accumulation of fine-grained alluvia was a reflection of intensified delivery of slope material into valley floors from catchments deforested by the Wallachians. The later stage of vertical incision of channels resulted from the decrease of sediment supply from hillslopes to river channels during catchment depopulation and afforestation.

Modeling the terrestrial N processes in a small mountain catchment through INCA-N: A case study in Taiwan

Riverine dissolved inorganic nitrogen (DIN) is an important indicator of trophic status of aquatic ecosystems. High riverine DIN export in Taiwan, ~3800kg-Nkm−2yr−1, which is ~18 times higher than the global average, urges the need of thorough understanding of N cycling processes. We applied INCA-N (Integrated Nitrogen Catchment Model) to simulate riverine DIN export and infer terrestrial N processes using weekly rainwater and streamwater samples collected at the Fushan Experimental Forest (FEF) of northern Taiwan. Results showed that the modeled discharge and nitrate export are in good agreement with observations, suggesting the validity of our application. Based on our modeling, the three main N removal processes, in the order of descending importance, were plant uptake, riverine N transport and denitrification at FEF. The high plant uptake rate, 4920kg-Nkm−2yr−1, should have led to accumulation of large biomass but biomass at FEF was relatively small compared to other tropical forests, likely due to periodic typhoon disruptions. The low nitrate concentration but high DIN export highlights the importance of hydrological control over DIN export, particularly during typhoons. The denitrification rate, 750kg-Nkm−2yr−1, at FEF was also low compared to other tropical forest ecosystems, likely resulting from quick water drainage through the coarse-loamy top soils. The high DIN export to atmospheric deposition ratio, 0.45, suggests that FEF may be in advanced stages of N excess. This simulation provides useful insights for establishing monitoring programs and improves our understanding N cycling in subtropical watersheds.

The role of catastrophic floods in shaping the morphology of river beds in small mountain catchment areas

Abstract Mountain streams are subjected to the continuous reshaping of their river beds during floods, with the greatest changes occurring during extreme floods caused by sudden and heavy rainfall. River bed transformations during these flash floods are more severe in forested areas, where wooden logs carried by swollen streams are more likely to be deposited on the ground, which in turn leads to the greater accumulation of other transported material and debris. The study was conducted in the Rybny Potok catchment area (Babia Góra National Park). An extreme flash flood occurred on 15–16 May 2014 because of heavy rainfall, which, on 15 May amounted to 138 mm. The total amount of precipitation in the catchment area was 216.5 mm in three days. This resulted in sudden and full streams in spate, contributing to significant geomorphological transformations reaching all the way to the bottom of the river beds. During the flash flood, already established river beds and streams increased in size and many new river courses were formed.

Automated convective and stratiform precipitation estimation in a small mountainous catchment using X-band radar data in Central Spain

For the purposes of weather nowcasting, flood risk monitoring and water resources assessment, it is often difficult to achieve a reliable spatio-temporal representation of rainfall due to a low rain gauge network density. However, quantitative precipitation estimation (QPE) has acquired new prospects with the introduction of weather radars, thanks to their higher spatio-temporal resolution. Although a wide number of QPE algorithms are available for using C-band radar data, only a few studies have employed X-band radar. In this study the microscale rainfall variability in a small catchment is automatically measured using short-range X-band radar variograms and classifying precipitation into convective and stratiform types with a recently published index. The aim is to apply a straightforward geostatistical algorithm, named ordinary kriging of radar errors (OKRE), to integrate X-band radar and rain gauge measurements in a mountainous catchment (15 km2) in central Spain. As expected, convective events presented higher estimation errors due to their complex spatial and temporal variability. Despite this fact, errors are sufficiently small and results are reliable rainfall estimations. The two main contributions of this work are the adaptation of the OKRE method to small spatial scales and its application automatically differentiating between convective and stratiform events.

Measuring alluvial fan sensitivity to past climate changes using a self‐similarity approach to grain‐size fining, Death Valley, California

AbstractThe effects of climate change on eroding landscapes and the terrestrial sedimentary record are poorly understood. Using mountain catchment–alluvial fan systems as simple analogues for larger landscapes, a wide range of theoretical studies, numerical models and physical experiments have hypothesized that a change in precipitation rate could leave a characteristic signal in alluvial fan sediment flux, grain size and down‐system fining rate. However, this hypothesis remains largely untested in real landscapes. This study measures grain‐size fining rates from apex to toe on two alluvial fan systems in northern Death Valley, California, USA, which each have well‐exposed modern and ca 70 ka surfaces, and where the long‐term tectonic boundary conditions can be constrained. Between them, these surfaces capture a well‐constrained temporal gradient in climate. A grain‐size fining model is adapted, based on self‐similarity and selective deposition, for application to these alluvial fans. This model is then integrated with cosmogenic nuclide constraints on catchment erosion rates, and observed grain‐size fining data from two catchment‐fan systems, to estimate the change in sediment flux from canyon to alluvial fan that occurred between mid‐glacial and modern interglacial conditions. In a fan system with negligible sediment recycling, a ca 30% decrease in precipitation rate led to a 20% decrease in sediment flux and a clear increase in the down‐fan rate of fining, supporting existing landscape evolution models. Consequently, this study shows that small mountain catchments and their alluvial fan stratigraphy can be highly sensitive to orbital climate changes over <105 year timescales. However, in the second fan system it is observed that this sensitivity is completely lost when sediment is remobilized and recycled over a time period longer than the duration of the climatic perturbation. These analyses offer a new approach to quantitatively reconstructing the effects of past climate changes on sedimentation, using simple grain‐size data measured in the field.

Effect of deforestation on stream water chemistry in the Skrzyczne massif (the Beskid Śląski Mountains in southern Poland)

The purpose of the study was to identify the factors affecting stream water chemistry in the small mountain catchments deforested to varying degrees, from 98.7 to 14.1%, due to long-term acid deposition. Water samples were collected monthly in 2013 and 2014 from 17 streams flowing across three distinct elevation zones in the Skrzyczne massif (Poland): Upper, Middle and Lower Forest Zone. Chemical and physical analyses, including the pH, electrical conductivity (EC), total mineral content (Mt), water temperature, and the concentrations of Ca2+, Mg2+, Na+, K+, HCO3−, SO42−, Cl−, and NO3−, were conducted. Based on Principal Component Analysis (PCA), the most important factor affecting water chemistry was human impact associated with changes in pH, SO42− concentration, and the concentration of most of the main ions. The substantial acidity of the studied environment contributed to the exclusion of natural factors, associated with changes in discharge, from the list of major factors revealed by PCA. All of the streams were characterized by very low EC, Mt, and low concentrations of the main ions such as Ca2+ and HCO3−. This is the effect of continuous leaching of solutes from the soils by acidic precipitation. The lowest parameter values were measured for the streams situated in the Upper Forest Zone, which is associated with greater acid deposition at the higher elevations. In the streams located in the Upper Forest Zone, a higher percentage of SO42− occurred than in the streams situated in the Middle and Lower Forest Zones. However, the largest share of SO42− was measured in the most deforested catchment. The saturation of the studied deforested catchment with sulfur compounds is reflected by a positive correlation between SO42− and discharge. Hence, a forest acts as a natural buffer that limits the level of acidity in the natural environment caused by acidic atmospheric deposition.

Sediment Reallocations due to Erosive Rainfall Events in the Three Gorges Reservoir Area, Central China

AbstractSoil erosion by water outlines a major threat to the Three Gorges Reservoir Area in China. A detailed assessment of soil conservation measures requires a tool that spatially identifies sediment reallocations due to rainfall–runoff events in catchments. We applied EROSION 3D as a physically based soil erosion and deposition model in a small mountainous catchment. Generally, we aim to provide a methodological frame that facilitates the model parametrization in a data scarce environment and to identify sediment sources and deposits. We used digital soil mapping techniques to generate spatially distributed soil property information for parametrization. For model calibration and validation, we continuously monitored the catchment on rainfall, runoff and sediment yield for a period of 12 months. The model performed well for large events (sediment yield > 1 Mg) with an averaged individual model error of 7.5%, while small events showed an average error of 36.2%. We focused on the large events to evaluate reallocation patterns. Erosion occurred in 11.1% of the study area with an average erosion rate of 49.9 Mg ha−1. Erosion mainly occurred on crop rotation areas with a spatial proportion of 69.2% for ‘corn‐rapeseed’ and 69.1% for ‘potato‐cabbage’. Deposition occurred on 11.0%. Forested areas (9.7%), infrastructure (41.0%), cropland (corn‐rapeseed: 13.6%, potato‐cabbage: 11.3%) and grassland (18.4%) were affected by deposition. Because the vast majority of annual sediment yields (80.3%) were associated to a few large erosive events, the modelling approach provides a useful tool to spatially assess soil erosion control and conservation measures. Copyright © 2016 John Wiley & Sons, Ltd.

Interplay between land use changes and soil erosion in a small mountainous catchment in southern Italy

Land use is one of the most important factors controlling soil erosion. Moreover, erosion rates may vary through time as a response to land use changes. The aim of this work was to analyze the main land use changes in the last 60 years and to assess the relationships between them and spatial and temporal distribution of soil loss at catchment scale.The study was carried out in the Torano catchment (northern Calabria), which is representative of wide sectors of Calabria Region, where the overall soil erosion susceptibility is high. Aerial photos interpretation of different years (1954 and 2012), and field survey were used to assess and map types and variations of land use in the study area. The mean annual rate of soil erosion and the effects of land use changes on soil erosion since 1954 to 2014 were analyzed by using the revised universal soil loss equation (RUSLE) in a GIS environment.Results showed that the total soil loss estimated in the Torano catchment was 2216.76 t yr-1 in 1954, 3242.22 t yr-1 in 2014. Furthermore, the rate of mean annual soil loss increased from 4.30 t ha-1 yr-1 in 1954 to 6.29 t ha-1 yr-1 in 2014. Increasing erosion rates was mainly caused by the transformation of natural forest, scrub and pasture areas into crop fields. In addition, from 1954 to 2014 the barren land progressively increased from 0.2% to more than 2 %; in these areas and the highest soil loss values were observed. The increase of cultivated and barren lands, from 1954 to 2014, caused a 46.3 % increase soil loss. Therefore, the spatio-temporal changes of land use in the Torano catchment had an important role on soil erosion control.

Spatial and temporal variation of the soil moisture regime along a hillslope segment and a small mountain catchment

Relationship between spatial patterns of soil moisture pressure head, soil depth and topography is important to understand factors controlling the dynamics of infiltrated rainwater into the soil matrix. We analysed the spatial and temporal variability of soil moisture pressure head in a small catchment (0.2 ha) and along a heavily instrumented hillslope transect (25 m long) within a roaded catchment in the Fudoji experimental watershed, Shiga, Japan. We monitored these variations at different depths on 51 observation nodes on both sites. The pressure head measurements on the hillslope segment located within the roaded catchment revealed the importance of topography and geomorphic processes in dictating the propagation of the soil water pressure head. Geomorphic process strongly contributed to the variability in soil depth and soil vertical profiles of the upper, middle and lower parts of the hillslope segment. Similarly, results from systematically installed observation nodes on the small catchment shows a spatially organised soil moisture variation with depth in a relatively flat segment of the planar topographic unit. The changes in micro-topography and soil depth highly dictate the routing of infiltrated water to downslope sections and thus the amount of water stored in the soil profiles.

Evaluation of runoff response on the basis of a comparative paired research in mountain catchments with the different land use: case study of the Blanice River, Czechia

The paper evaluates the runoff response in two small mountain catchments on the basis of a comparative paired research in the headwater area of the Blanice River, south Bohemia. The predominantly grassy Zbytinský potok and forested Tetřívčí potok brooks represent the headwaters landscape of the eastern part of the Šumava Mountains. Differences in runoff response are observed on the principle of black box from the two points of view: long-term water balance characteristics and rainfall-runoff events. Despite the average lower runoff values, the forested Tetřívčí potok brook showed a more significant runoff response in most events, mainly in wet years, and the total higher variability of runoff. It has a significantly higher runoff during a dry period. The research is based on the own data obtained by continual monitoring of the water level, discharge and precipitation. The presented study wants to assess the differences in the behaviour of both hydrological systems, especially their response to a causal rainfall.

Massive biomass flushing despite modest channel response in the Rayas River following the 2008 eruption of Chaitén volcano, Chile

The 2008 eruption of Chaitén volcano in southern Chile severely impacted several densely forested river catchments by supplying excess pyroclastic sediment to the channel networks. Our aim is to substantiate whether and how channel geometry and forest stands changed in the Rayas River following the sudden input of pyroclastic sediment. We measured the resulting changes to channel geometry and riparian forest stands along 17.6km of the impacted gravel-bed Rayas River (294km2) from multiple high-resolution satellite images, aerial photographs, and fieldwork to quantify yield volume characteristics of the forest stands. Limited channel changes during the last 60years before the eruption reflect a dynamic equilibrium condition of the river corridor, despite the high annual precipitation and the sediment supply from Chaitén and Michinmahuida volcanoes in the headwaters. Images taken in 1945, 2004, and 2005 show that total size of the vegetated channel islands nearly doubled between 1945 and 2004 and remained unchanged between 2004 and 2005. Pyroclastic sediment entering the Rayas River after the 2008 eruption caused only minor average channel widening (7%), but killed all island vegetation in the study reach. Substantial shifts in the size distribution of in-channel vegetation patches reflect losses in total island area of 46% from 2005 to 2009 and an additional 34% from 2009 to 2012. The estimated pulsed release of organic carbon into the channel, mainly in the form of large wood from obliterated island and floodplain forests, was 78–400tC/km/y and surpasses most documented yields from small mountainous catchments with similar rainfall, forest cover, and disturbance history, while making up between 20% and 60% of the annual carbon burial rate of fluvial sediments in the northern Patagonian fjords. We conclude that the carbon footprint of the 2008 Chaitén eruption on the Rayas River was more significant than the measured geomorphic impacts on channel geometry for the first five years following disturbance. The modest post-eruptive geomorphic response in this river is a poor indicator of its biogeochemical response.

Field test of a multi-frequency electromagnetic induction sensor for soil moisture monitoring in southern Italy test sites

Summary Soil moisture is a variable of paramount importance for a number of natural processes and requires the capacity to be routinely measured at different spatial and temporal scales (e.g., hillslope and/or small catchment scale). The electromagnetic induction (EMI) method is one of the geophysical techniques potentially useful in this regard. Indeed, it does not require contact with the ground, it allows a relatively fast survey of hillslope, it gives information related to soil depth greater than few centimetres and it can also be used in wooded areas. In this study, apparent electrical conductivity (ECa) and soil moisture (SM) measurements were jointly carried out by using a multi-frequency EMI sensor (GEM-300) and Time Domain Reflectometry (TDR) probes, respectively. The aim was to retrieve SM variations at the hillslope scale over four sites, characterized by different land-soil units, located in a small mountainous catchment in southern Italy. Repeated measurements of ECa carried out over a fixed point showed that the signal variability of the GEM-300 sensor (Std. Err. ∼[0.02–0.1 mS/m]) was negligible. The correlation estimated between point ECa and SM, measured with both portable and buried TDR probes, varied between 0.24 and 0.58, depending on the site considered. In order to reduce the effect of small-scale variability, a spatial smoothing filter was applied which allowed the estimation of linear relationships with higher coefficient of correlation (r ∼ 0.46–0.8). The accuracy obtained in the estimation of the temporal trend of the soil moisture spatial averages was in the range ∼4.5–7.8% v/v and up to the ∼70% of the point soil moisture variance was explained by the ECa signal. The obtained results highlighted the potential of EMI to provide, in a short time, sufficiently accurate estimate of soil moisture over large areas that are highly needed for hydrological and remote sensing applications.

Uncertainty assessment of soil erosion model using particle filtering

Recent advances in computer with geographic information system (GIS) technologies have allowed modelers to develop physics-based models for modeling soil erosion processes in time and space. However, it has been widely recognized that the effect of uncertainties on model predictions may be more significant when modelers apply such models for their own modeling purposes. Sources of uncertainty involved in modeling include data, model structural, and parameter uncertainty. To deal with the uncertain parameters of a catchment-scale soil erosion model (CSEM) and assess simulation uncertainties in soil erosion, particle filtering modeling (PF) is introduced in the CSEM. The proposed method, CSEM-PF, estimates parameters of non-linear and non-Gaussian systems, such as a physics-based soil erosion model by assimilating observation data such as discharge and sediment discharge sequences at outlets. PF provides time-varying feasible parameter sets as well as uncertainty bounds of outputs while traditional automatic calibration techniques result in a time-invariant global optimal parameter set. CSEM-PF was applied to a small mountainous catchment of the Yongdam dam in Korea for soil erosion modeling and uncertainty assessment for three historical typhoon events. Finally, the most optimal parameter sets and uncertainty bounds of simulation of both discharge and sediment discharge at each time step of the study events are provided.

Seasonal changes in runoff generation in a small forested mountain catchment

AbstractThis study aimed to investigate the seasonal variability of runoff generation processes, the sources of stream water, and the controls on the contribution of event water to streamflow for a small forested catchment in the Italian pre‐Alps. Hydrometric, isotopic, and electrical conductivity data collected between August 2012 and August 2013 revealed a marked seasonal variability in runoff responses. Noticeable differences in runoff coefficients and hydrological dynamics between summer and fall/spring rainfall events were related to antecedent moisture conditions and event size. Two‐component and three‐component hydrograph separation and end‐member mixing analysis showed an increase in event water contributions to streamflow with event size and average rainfall intensity. Event water fractions were larger during dry conditions in the summer, suggesting that stormflow generation in the summer consisted predominantly of direct channel precipitation and some saturated overland flow from the riparian zone. On the contrary, groundwater and hillslope soil water contributions dominated the streamflow response during wet conditions in fall. Seasonal differences were also noted between event water fractions computed based on isotopic and electrical conductivity data, likely because of the dilution effect during the wetter months. Copyright © 2014 John Wiley & Sons, Ltd.

Sensitivity of the Snowmelt Runoff Model to snow covered area and temperature inputs

Snowpack is an important source of freshwater. Snowmelt runoff models provide a means to predict the timing and magnitude of spring snowmelt. This study assessed the sensitivity of the conceptual, degree-day Snowmelt Runoff Model (SRM) to snow covered area and temperature inputs in a small mountainous catchment in Utah, USA. It was found that snow cover products from the Moderate Resolution Imaging Spectroradiometer (MODIS) underestimate snow covered area during the second half of the melt season, leading to inadequate modeling of spring snowmelt with SRM (Nash-Sutcliffe Efficiency = 0.59; bias of −26.9%). Incorporation of ancillary snow covered area information provided by Landsat ETM+ imagery greatly improved streamflow simulations (Nash-Sutcliffe Efficiency = 0.92; bias of −0.01%). For the temperature input, SRM appeared more sensitive to the elevation and location of the temperature reference station than to the lapse rate scenario used to extrapolate temperatures throughout the watershed. These findings will be useful for snowmelt runoff research and water resource management.

Dendrogeomorphic reconstruction of flash floods in the Patagonian Andes

Flash floods represent a significant natural hazard in small mountainous catchments of the Patagonian Andes and have repeatedly caused loss to life and infrastructure. At the same time, however, documentary records of past events remain fairly scarce and highly fragmentary in most cases. In this study, we therefore reconstruct the spatiotemporal patterns of past flash flood activity along the Los Cipreses torrent (Neuquén, Argentina) using dendrogeomorphic methods. Based on samples from Austrocedrus chilensis, Pseudotsuga menziesii, and Nothofagus dombeyi, we document 21 flash flood events covering the period A.D. 1890–2009 and reconstruct mean recurrence intervals of events at the level of individual trees being impacted, which varies from 4 to 93years. Results show that trees tend to be older (younger) in sectors of the torrent with gentler (steeper) slope gradients. Potential triggers of flash floods were analyzed using daily temperature and precipitation data from a nearby weather station. Weather conditions leading to flash floods are abundant precipitations during one to three consecutive days, combined with temperatures above the rain/snow threshold (2°C) in the whole watershed.

Monitoring sediment source areas in a debris-flow catchment using terrestrial laser scanning

Geomorphic changes caused by three debris-flow events in a small mountain catchment (Moscardo Torrent, Eastern Italian Alps) were investigated by means of multitemporal terrestrial laser scanning (TLS) surveys over three areas exposed to debris-flow dynamics. For these areas, DEM of Differences (DoDs) with a 0.2m spatial resolution allowed the assessment of elevation uncertainty as spatially variable by applying the fuzzy inference system (FIS) proposed by Wheaton et al. (2010). Along with two commonly used parameters affecting Digital Elevation Model (DEM) accuracy, such as terrain slope and point density, we developed and employed in the FIS a new index, named Vegetation Noise, that takes into account the disturbance caused by the vegetation cover on the DEM accuracy. The results of volumetric budgets of the surveyed sediment source areas derived from the DoD analysis were compared with debris-flow volumes estimated from flow stage measurements at the instrumented channel reach. On the one hand, the discrepancies arising from this comparison underline the limitations of TLS surveys over morphologically complex areas such as debris-flow catchments. On the other hand, the TLS unveils the geomorphic changes at the scale of the single event, because a terrestrial survey is usually easier to carry out than an aerial one. The analysis of DEM quality and uncertainty indexes correlation may help to refine methods for spatializing elevation errors and improving the reliability of the models.

Temporal variations of reservoir sediment sources in a small mountainous catchment in Korea

ABSTRACTAn understanding of the temporal variation in reservoir sedimentation and identification of the main sources of sediment are necessary for the maintenance of sustainable reservoirs. For this purpose, field measurements, sampling, and fingerprinting of reservoir sediment were undertaken from July 2005 to November 2007. Source fingerprinting of reservoir sediment was conducted using cesium‐137 (137Cs). The relative contributions of gully bank and forest road, and forest floor material to reservoir sediment were calculated using a mixing model. Bank and forest road material, estimated to make up about 96% of the reservoir sediment, was the dominant source. Enormous reservoir sedimentation, which amounted to about 60% of the total reservoir sedimentation during the observation period, occurred during a heavy rainstorm with an 80‐year recurrence time. To maintain the sustainability of the reservoir in this study, therefore, temporal and spatial preparation strategies for heavy rainstorms and bank and forest road erosion should be considered. However, spatial information on sediment sources from 137Cs fingerprinting is limited. To better identify the sediment sources spatially and temporally, further studies applying soil erosion models and more detailed field studies are needed. Copyright © 2013 John Wiley & Sons, Ltd.

Phoenix Debris-Flow Hazard Assessment: House Location Matters

Three catchments that debouch into Phoenix housing developments from the Ma Ha Tuak Range, South Mountain show a consistent pattern of declines in the magnitude of debris flows over time. We used a mix of field and geospatial methods to estimate volume, and the varnish microlamination technique to estimate minimum ages of debris deposits. Estimates of debris-flow volumes show a drop of more than two orders of magnitude from latest Pleistocene to 20th century or Little Ice Age. Debris-flow run-out lengths also shortened tremendously, with the most recent events stopping inside incised channels. In contrast, a catchment above houses in the Gila Range, South Mountain, where houses were built very close to the debris-flow source area, reveals an increase in debris-flow magnitude over time. These contrasting findings emphasize the importance of the location of home sites with respect to the debris-flow system in the type of small desert mountain catchments that interface with the sprawling urbanism found in Southwestern USA deserts.

MODIS snow cover mapping accuracy in a small mountain catchment – comparison between open and forest sites

Abstract. Numerous global and regional validation studies have examined MODIS snow mapping accuracy by using measurements at climate stations, which are mainly at open sites. MODIS accuracy in alpine and forested regions is, however, still not well understood. The main objective of this study is to evaluate MODIS (MOD10A1 and MYD10A1) snow cover products in a small experimental catchment by using extensive snow course measurements at open and forest sites. The MODIS accuracy is tested in the Jalovecky creek catchment (northern Slovakia) in the period 2000–2011. The results show that the combined Terra and Aqua images enable snow mapping at an overall accuracy of 91.5%. The accuracies at forested, open and mixed land uses at the Červenec sites are 92.7%, 98.3% and 81.8%, respectively. The use of a 2-day temporal filter enables a significant reduction in the number of days with cloud coverage and an increase in overall snow mapping accuracy. In total, the 2-day temporal filter decreases the number of cloudy days from 61% to 26% and increases the snow mapping accuracy to 94%. The results indicate three possible factors leading to misclassification of snow as land: patchy snow cover, limited MODIS geolocation accuracy and mapping algorithm errors. Out of a total of 27 misclassification cases, patchy snow cover, geolocation issues and mapping errors occur in 12, 12 and 3 cases, respectively.