We present an annual reconstruction of extreme rainfall events interpreted from detrital layers a... more We present an annual reconstruction of extreme rainfall events interpreted from detrital layers and turbidites interbedded within a varved sediment record since the 14 th century in Montcortés Lake (NE Spain, 1027 m a.s.l.). Clastic microfacies intercalated within the biochemical calcite varves were characterized and their depositional dynamics interpreted using high-resolution geochemical and sedimentological analyses. Annual number of detrital layers was compared against instrumental records of extreme daily rainfalls providing minimum rainfall thresholds and return periods associated to the identified types of clastic microfacies. Non-continuous detrital layers were deposited during rainfall events higher than 80 mm (>2-year return period) while graded detrital layers and turbidites were associated with higher magnitude rainfall events (>90 mm and >4-year return period). The frequency distribution of extreme hydro-meteorological events is not stationary and its pattern coincides with historical floods from the nearby Segre River. High frequency of heavy rainfalls occurred during the periods AD 1347e1400 and AD 1844e1894. A lower frequency of heavy rainfall was found during the periods AD 1441e1508, 1547e1592, 1656e1712, 1765e1822 and 1917e2012. The 20 th century stands out as the longest interval within the studied period of very low number of extreme rainfall events. Variability in extreme rainfall events prior to the 20 th century is in phase with solar activity, suggesting a mechanistic link in mid-latitude atmospheric circulation patterns that ceased during the 20 th century.
The Guadaletín River, located in SE Spain, is considered one of the most torrential rivers in Spa... more The Guadaletín River, located in SE Spain, is considered one of the most torrential rivers in Spain (e.g. the 1879 flood resulted in 777 casualties in the Murcia region; the Puentes dam break in 1802 caused 608 deaths in Lorca). Flash flood magnitude and frequency of the upper Guadalentín River has been reconstructed using documentary sources and geological evidence. Documentary
1] Better understanding of flood occurrences and long-term, floodplain planning, and flood risk a... more 1] Better understanding of flood occurrences and long-term, floodplain planning, and flood risk assessment is achieved by integration of gauged, historical, and paleoflood data. The Ardèche River is ideal for this historical flood-paleoflood study because its historical flood levels record dates back as early as A.D. 587 and useful data date back to A.D. 1522, its systematic gauging record is over 100 years long, and the geologic and geomorphic settings are optimal for paleoflood studies. Three sites provide three different thresholds for flood stages and SWD accumulation. According to our onedimensional (1-D) step-backwater calculations these three thresholds are 5200-5700 m 3 s À1 , 4900-5400 m 3 s À1 , and 3600-4000 m 3 s À1 recording 6, 9, and 19 large Holocene floods, respectively. Dating the deposits enabled a correlation with the historical record. These paleoflood studies indicate that there are long gaps in flood occurrences on the Ardèche River; the floods are not randomly distributed in time but are clustered. They also indicate that the recent nineteenth century floods were the largest at the millennial timescale.
The Swakop River is a major ephemeral river (drainage basin area about 30,000 km 2 ) crossing the... more The Swakop River is a major ephemeral river (drainage basin area about 30,000 km 2 ) crossing the western Namib Desert. Its hydrology and limited water resources depend on storms and floods. Therefore, the hydrology and flow regime in the Swakop River basin determines the availability of water for human use. In this study we present a millennia-long record of extreme floods, using paleoflood hydrological methods and optically stimulated luminescence (OSL) ages. The record includes 44 large floods ranging in date from the late Pleistocene to the present. The oldest six to eight floods are dated from the late Pleistocene to the mid-Holocene (between 14,900 ± 1700 and 5100 ± 620 years ago), with calculated peak discharges of 550e1280 m 3 s À1 . Eighteen floods, eleven of which were between 1000 and 1600 m 3 s À1 , occurred between 740 ± 90 and 190 ± 10 years ago. Additional 17 later floods occurred between about AD 1850 and 1963, with peak discharges between 100 and 1000 m 3 s À1 . The historical record which partly parallels the latter period recorded 17 large floods during the period 1893e1963. Flood frequency analysis (FFA) of the combined systematically gaged record (1963e2003) and the paleoflood record since AD 1270 (740 ± 90 years, the most complete record), was applied using the maximum likelihood method. A two-component extreme value distribution (TCEV) estimates the 1% annual exceedance probability magnitude, using only the systematic gaged record at 520 m 3 s À1 . The combined paleoflood, historical, and gage records resulted in a much larger magnitudes for the 1% annual exceedance probability flood magnitude of 1320e1350 m 3 s À1 . The 0.1% annual exceedance probability magnitude is estimated at 770 m 3 s À1 and 2100e2150 m 3 s À1 , respectively.
ABSTRACT This work describes the methodological procedure and the instrumentation installed to mo... more ABSTRACT This work describes the methodological procedure and the instrumentation installed to monitor the infiltration through the vadose zone associated with flood events of the Andarax River (Almeria). First, the preliminary data recorded in the station's first functional year are presented and discussed. The final objective of this monitoring was to quantify the long-term shallow alluvial aquifer recharge related to flooding. The monitoring station is located near Gador, and records the moisture contents through the vadose profile using 15 flexible TDR probes (FTDR) reaching depths of 10 m. In addition, water surface and groundwater piezometric levels are recorded. The preliminary results clearly show that the methodology chosen permits the collection of real time and continuous infiltration data in the vadose zone with minimum soil disturbances. The 7 January 2006 event recorded, 7 days in length and whose maximum flood height recorded was 7 centimeters, demonstrated that the flood hydrograph gave a clear response in the soil moisture content of the profile studied, with increases in soil water content of up to 5% for soil depths below 9 meters. Analyzing the changes in the ground water level it is obvious that the infiltration data can be applied to the whole vadose zone and therefore the aquifer recharge can be estimated.
En realidad, la capacidad de tener presentes a las generaciones futuras, es decir, a los miembros... more En realidad, la capacidad de tener presentes a las generaciones futuras, es decir, a los miembros no natos de nuestra especie, es precisamente uno de nuestros hechos diferenciales como especie. También lo es la capacidad, que nos ofrece la tecnología, de haber multiplicado nuestro poder de transformación y de consumo, la capacidad de utilizar nuestro conocimiento para duplicar la esperanza de vida y la capacidad de utilizar la tecnología para reemplazar el lento proceso de la evolución y generar decenas de miles de nuevos compuestos químicos, que no están inscritos en nuestro genoma, sino que hemos externalizado y desarrollado a través de la tecnología. Estas capacidades y las enormes perspectivas que ofrecen para la mejora de nuestra calidad de vida se han utilizado sin plena conciencia de las consecuencias que, conjuntamente, tienen sobre la naturaleza y sobre el funcionamiento del planeta Tierra; posiblemente porque la capacidad de contemplar el planeta como unidad funcional se h...
We present an annual reconstruction of extreme rainfall events interpreted from detrital layers a... more We present an annual reconstruction of extreme rainfall events interpreted from detrital layers and turbidites interbedded within a varved sediment record since the 14 th century in Montcortés Lake (NE Spain, 1027 m a.s.l.). Clastic microfacies intercalated within the biochemical calcite varves were characterized and their depositional dynamics interpreted using high-resolution geochemical and sedimentological analyses. Annual number of detrital layers was compared against instrumental records of extreme daily rainfalls providing minimum rainfall thresholds and return periods associated to the identified types of clastic microfacies. Non-continuous detrital layers were deposited during rainfall events higher than 80 mm (>2-year return period) while graded detrital layers and turbidites were associated with higher magnitude rainfall events (>90 mm and >4-year return period). The frequency distribution of extreme hydro-meteorological events is not stationary and its pattern coincides with historical floods from the nearby Segre River. High frequency of heavy rainfalls occurred during the periods AD 1347e1400 and AD 1844e1894. A lower frequency of heavy rainfall was found during the periods AD 1441e1508, 1547e1592, 1656e1712, 1765e1822 and 1917e2012. The 20 th century stands out as the longest interval within the studied period of very low number of extreme rainfall events. Variability in extreme rainfall events prior to the 20 th century is in phase with solar activity, suggesting a mechanistic link in mid-latitude atmospheric circulation patterns that ceased during the 20 th century.
The Guadaletín River, located in SE Spain, is considered one of the most torrential rivers in Spa... more The Guadaletín River, located in SE Spain, is considered one of the most torrential rivers in Spain (e.g. the 1879 flood resulted in 777 casualties in the Murcia region; the Puentes dam break in 1802 caused 608 deaths in Lorca). Flash flood magnitude and frequency of the upper Guadalentín River has been reconstructed using documentary sources and geological evidence. Documentary
1] Better understanding of flood occurrences and long-term, floodplain planning, and flood risk a... more 1] Better understanding of flood occurrences and long-term, floodplain planning, and flood risk assessment is achieved by integration of gauged, historical, and paleoflood data. The Ardèche River is ideal for this historical flood-paleoflood study because its historical flood levels record dates back as early as A.D. 587 and useful data date back to A.D. 1522, its systematic gauging record is over 100 years long, and the geologic and geomorphic settings are optimal for paleoflood studies. Three sites provide three different thresholds for flood stages and SWD accumulation. According to our onedimensional (1-D) step-backwater calculations these three thresholds are 5200-5700 m 3 s À1 , 4900-5400 m 3 s À1 , and 3600-4000 m 3 s À1 recording 6, 9, and 19 large Holocene floods, respectively. Dating the deposits enabled a correlation with the historical record. These paleoflood studies indicate that there are long gaps in flood occurrences on the Ardèche River; the floods are not randomly distributed in time but are clustered. They also indicate that the recent nineteenth century floods were the largest at the millennial timescale.
The Swakop River is a major ephemeral river (drainage basin area about 30,000 km 2 ) crossing the... more The Swakop River is a major ephemeral river (drainage basin area about 30,000 km 2 ) crossing the western Namib Desert. Its hydrology and limited water resources depend on storms and floods. Therefore, the hydrology and flow regime in the Swakop River basin determines the availability of water for human use. In this study we present a millennia-long record of extreme floods, using paleoflood hydrological methods and optically stimulated luminescence (OSL) ages. The record includes 44 large floods ranging in date from the late Pleistocene to the present. The oldest six to eight floods are dated from the late Pleistocene to the mid-Holocene (between 14,900 ± 1700 and 5100 ± 620 years ago), with calculated peak discharges of 550e1280 m 3 s À1 . Eighteen floods, eleven of which were between 1000 and 1600 m 3 s À1 , occurred between 740 ± 90 and 190 ± 10 years ago. Additional 17 later floods occurred between about AD 1850 and 1963, with peak discharges between 100 and 1000 m 3 s À1 . The historical record which partly parallels the latter period recorded 17 large floods during the period 1893e1963. Flood frequency analysis (FFA) of the combined systematically gaged record (1963e2003) and the paleoflood record since AD 1270 (740 ± 90 years, the most complete record), was applied using the maximum likelihood method. A two-component extreme value distribution (TCEV) estimates the 1% annual exceedance probability magnitude, using only the systematic gaged record at 520 m 3 s À1 . The combined paleoflood, historical, and gage records resulted in a much larger magnitudes for the 1% annual exceedance probability flood magnitude of 1320e1350 m 3 s À1 . The 0.1% annual exceedance probability magnitude is estimated at 770 m 3 s À1 and 2100e2150 m 3 s À1 , respectively.
ABSTRACT This work describes the methodological procedure and the instrumentation installed to mo... more ABSTRACT This work describes the methodological procedure and the instrumentation installed to monitor the infiltration through the vadose zone associated with flood events of the Andarax River (Almeria). First, the preliminary data recorded in the station's first functional year are presented and discussed. The final objective of this monitoring was to quantify the long-term shallow alluvial aquifer recharge related to flooding. The monitoring station is located near Gador, and records the moisture contents through the vadose profile using 15 flexible TDR probes (FTDR) reaching depths of 10 m. In addition, water surface and groundwater piezometric levels are recorded. The preliminary results clearly show that the methodology chosen permits the collection of real time and continuous infiltration data in the vadose zone with minimum soil disturbances. The 7 January 2006 event recorded, 7 days in length and whose maximum flood height recorded was 7 centimeters, demonstrated that the flood hydrograph gave a clear response in the soil moisture content of the profile studied, with increases in soil water content of up to 5% for soil depths below 9 meters. Analyzing the changes in the ground water level it is obvious that the infiltration data can be applied to the whole vadose zone and therefore the aquifer recharge can be estimated.
En realidad, la capacidad de tener presentes a las generaciones futuras, es decir, a los miembros... more En realidad, la capacidad de tener presentes a las generaciones futuras, es decir, a los miembros no natos de nuestra especie, es precisamente uno de nuestros hechos diferenciales como especie. También lo es la capacidad, que nos ofrece la tecnología, de haber multiplicado nuestro poder de transformación y de consumo, la capacidad de utilizar nuestro conocimiento para duplicar la esperanza de vida y la capacidad de utilizar la tecnología para reemplazar el lento proceso de la evolución y generar decenas de miles de nuevos compuestos químicos, que no están inscritos en nuestro genoma, sino que hemos externalizado y desarrollado a través de la tecnología. Estas capacidades y las enormes perspectivas que ofrecen para la mejora de nuestra calidad de vida se han utilizado sin plena conciencia de las consecuencias que, conjuntamente, tienen sobre la naturaleza y sobre el funcionamiento del planeta Tierra; posiblemente porque la capacidad de contemplar el planeta como unidad funcional se h...
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