Hydrologic behaviour of a mountainous watershed

1993 ◽  
Vol 20 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Athanasios Loukas ◽  
Michael C. Quick
Keyword(s):  
Soil Conditions ◽  
Hydrologic Response ◽  
Watershed Model ◽  
Watershed Modelling ◽  
Watershed Response ◽  
Hourly Data ◽  
Soil Piping ◽  
Dry Soil ◽  
Coastal British Columbia ◽  
Soil Pipe

A simplified watershed model has been developed to examine and analyze the high rainfall response of a small, steep, and forested watershed in coastal British Columbia. Hourly data for both rainfall and streamflow are used. Rainfall is measured at five points evenly distributed throughout the watershed. The model is found to perform well and indicates that the hydrologic response of the watershed is reasonably linear, except for intense summer rainstorms under dry soil conditions. The linearity and the rapidity of the watershed response is attributed to the response of the subsurface pipeflow. An analysis of a particular case of soil pipe development shows that the pipeflow system can respond linearly and rapidly to the rainfall input. Key words: watershed modelling, hydrologic response, soil piping.

scholarly journals White Root Rot of Raspberries

1951 ◽  
Vol 4 (3) ◽  
pp. 211
Author(s):  
GC Wade
Keyword(s):  
Soil Moisture ◽  
Root Rot ◽  
Soil Moisture Content ◽  
Soil Conditions ◽  
Causal Organism ◽  
White Root Rot ◽  
High Soil Moisture ◽  
High Soil ◽  
Soil Temperatures ◽  
Dry Soil

The disease known as white root rot affects raspberries, and to a less extent loganberries, in Victoria. The causal organism is a white, sterile fungus that has not been identified. The disease is favoured by dry soil conditions and high soil temperatures. It spreads externally to the host by means of undifferentiated rhizomorphs; and requires a food base for the establishment of infection. The spread of rhizomorphs through the soil is hindered by high soil moisture content and consequent poor aeration of the soil.

Factors affecting the phenology of the first brood of the sugar-cane froghopper Aeneolamia varia saccharina (Dist.) (Homoptera, Cercopidae) in Trinidad

1975 ◽  
Vol 65 (3) ◽  
pp. 359-372 ◽  
Author(s):  
A. B. S. King
Keyword(s):  
Adult Emergence ◽  
Dry Season ◽  
Soil Conditions ◽  
Factors Affecting ◽  
Expected Time ◽  
Short Period ◽  
Incubation Periods ◽  
Close Relationship ◽  
Dry Soil ◽  
Predictive Relationship

AbstractThe size and occurrence of the first brood of adults of Aeneolamia varia saccharina (Dist.) are examined in relation to the pattern of egg eclosion and rainfall. The proportion of eggs hatching within a month of oviposition in the laboratory (short-period eggs) decreased from over 90% in August to less than 20% in January, but the incubation periods of the remaining, long-period eggs were longest in those laid during October and November. The overall hatching distributions tended to be bimodal with most eggs hatching during the early months of the year under moist conditions at 26°C. Dry soil conditions delay eclosion, and eggs obtained from fields during the dry season and then incubated under moist conditions tended to hatch at the normally expected time of the first rains in May. The numbers of eggs expected to produce the first brood, computed from laboratory hatching data and estimates of the numbers and fecundities of froghoppers during the second, third and fourth broods, were less than the actual numbers sampled just before the first rains. There was a close relationship between the first rainfall of over one inch within 48 h and adult emergence 27 and 34 days later, and 85% of field egg populations in May had hatched and/or died by the week after the first rains. However some variation in the date of their occurrence accounted for non-synchrony of first broods over the region. The numbers of diapause eggs in fields sampled during the dry season failed to give a good predictive relationship with first brood adult populations, probably because of density dependent mortality of eggs or hatchling nymphs.

scholarly journals Numerical simulations of the impact of climate variability and change on semiarid watershed response in central New Mexico

2009 ◽  
Vol 6 (1) ◽  
pp. 319-371
Author(s):  
E. R. Vivoni ◽  
C. A. Aragón ◽  
L. Malczynski ◽  
V. C. Tidwell
Keyword(s):  
Climate Change ◽  
New Mexico ◽  
Summer Precipitation ◽  
Climate Change Scenarios ◽  
Hydrologic Response ◽  
Watershed Model ◽  
Precipitation Regime ◽  
Hydrologic Processes ◽  
Precipitation Characteristics ◽  
The Impact

Abstract. Hydrologic processes in the semiarid regions of the southwest United States are considered to be highly susceptible to variations in temperature and precipitation characteristics due to the effects of climate change. Relatively little is known on the potential impacts of climate change on the basin hydrologic response, namely streamflow, evapotranspiration and recharge, in the region. In this study, we present the development and application of a continuous, semi-distributed watershed model for climate change studies in semiarid basins of the southwest US. Our objective is to capture hydrologic processes in large watersheds, while accounting for the spatial and temporal variations of climate forcing and basin properties in a simple fashion. We apply the model to the Río Salado basin in central New Mexico since it exhibits both a winter and summer precipitation regime and has a historical streamflow record for model testing purposes. Subsequently, we utilize a sequence of climate change scenarios that capture observed trends for winter and summer precipitation, as well as their interaction with higher temperatures, to perform long-term ensemble simulations of the basin hydrologic response. Results of the modeling exercise indicate that precipitation uncertainty is amplified in the hydrologic response, in particular for processes that depend on a soil saturation threshold. We obtained substantially different hydrologic sensitivities for winter and summer precipitation ensembles, indicating a greater sensitivity to more intense summer storms as compared to more frequent winter events. In addition, the impact of changes in precipitation characteristics overwhelmed the effects of increased temperature in the study basin. Nevertheless, combined trends in precipitation and temperature yield a more sensitive hydrologic response throughout the year.

Quantifying the effect of post-wildfire soil water repellency on runoff

2021 ◽  
Author(s):  
Rose Shillito ◽  
Markus Berli ◽  
Ian Floyd ◽  
Li Chen ◽  
Teamrat Ghezzehei
Keyword(s):  
Soil Water ◽  
Water Repellency ◽  
Silica Sand ◽  
Watershed Model ◽  
Soil Water Repellency ◽  
Physically Based Model ◽  
San Gabriel Mountains ◽  
Physically Based ◽  
Dry Soil ◽  
Moisture Conditions

<p>Several factors are believed to contribute to post-wildfire flooding and debris flows. One contributing factor—the occurrence of post-wildfire soil water repellency—lacks a quantitative mechanism to incorporate the effects in physically-based runoff models. For this study, a physically-based model was developed linking the contact angle (degree of water repellency) to sorptivity. The model was verified in laboratory experiments using a silica sand proxy. The effects of water repellency on infiltration were illustrated. Further, the effect of water repellency on runoff was simulated using the AGWA-KINEROS2 watershed model with data from rainfall following the 2009 Station fire in the San Gabriel Mountains of southern California, USA. Results show water repellency has a quantifiable effect on runoff production, an effect enhanced by the dry soil moisture conditions common after wildfires.</p>

Absorption of 2,4-D, Dicamba, and Glyphosate by Excised Honeyvine Milkweed (Cynanchum Laeve) Leaves

Weed Science ◽  
1983 ◽  
Vol 31 (2) ◽  
pp. 271-274 ◽  
Author(s):  
John K. Soteres ◽  
Don S. Murray ◽  
Eddie Basler
Keyword(s):  
Surface Tension ◽  
Soil Conditions ◽  
Leaf Position ◽  
Drying Time ◽  
Leaf Surfaces ◽  
Anisic Acid ◽  
Dry Soil ◽  
The Difference ◽  
Dichlorophenoxy Acetic Acid ◽  
Reduced Surface

Absorption of 2,4-D [(2,4-dichlorophenoxy) acetic acid], dicamba [3,6-dichloro-o-anisic acid], and the isopropylamine salt of glyphosate [N-(phosphonomethyl) glycine] by excised honeyvine milkweed [Cynanchum laeve(Michx.) Pers.] leaves was determined. Experimental variables included leaf position (terminal vs. basal), a surfactant, 4-isopropenyl-1-methylcyclohexane plus unspecified emulsifiers (SA-77), and leaf collection dates. Absorption of the three herbicides by terminal and basal leaves was increased by the addition of the surfactant. However, the surfactant increased absorption into basal leaves more than into terminal leaves. The surfactant reduced surface tension and increased drying time of water droplets on adaxial leaf surfaces by 50%. The pH of the herbicide solutions was reduced from about 5.8 to about 3.9 by SA-77. Absorption of all three herbicides was greater into terminal than into basal leaves when the surfactant was not present, but the difference disappeared when the surfactant was added. Generally, no differences were observed in the absorption of 2,4-D and dicamba. Glyphosate absorption was greater in terminal leaves collected after a period of adequate moisture than after a period of dry soil conditions.

scholarly journals After-effect of long-term soil management on soil respiration and otherqualitative parameters under prolonged dry soil conditions

2015 ◽  
Vol 39 ◽  
pp. 633-651 ◽  
Author(s):  
Dalia FEIZIENE ◽  
Dalia JANUSAUSKAITE ◽  
Virginijus FEIZA ◽  
Agne PUTRAMENTAITE ◽  
Ausra SINKEVICIENE ◽  
...  
Keyword(s):  
Soil Respiration ◽  
Soil Management ◽  
Soil Conditions ◽  
After Effect ◽  
Dry Soil

scholarly journals Earthworms are little affected by reduced soil tillage methods in vineyards

2017 ◽  
Vol 63 (No. 6) ◽  
pp. 257-263 ◽  
Author(s):  
Faber Florian ◽  
Wachter Elisabeth ◽  
Zaller Johann G
Keyword(s):  
Soil Moisture ◽  
Soil Temperature ◽  
Soil Tillage ◽  
Soil Conditions ◽  
Reduced Tillage ◽  
No Tillage ◽  
Dry Soil ◽  
The Impact ◽  
Tillage Methods ◽  
Erosion Prevention

Inter-rows in vineyards are commonly tilled in order to control weeds and/or to conserve water. While impacts of tillage on earthworms are well studied in arable systems, very little is known from vineyards. In an experimental vineyard, the impact of four reduced tillage methods on earthworms was examined: rotary hoeing, rotary harrowing, grubbing and no tillage. According to an erosion prevention programme, tillage was applied every other inter-row only while alternating rows retained vegetated. Earthworms were extracted from the treated inter-rows 10, 36, 162 and 188 days after tillage. Across dates, tillage methods had no effect on overall earthworm densities or biomass. Considering each sampling date separately, earthworm densities were affected only at day 36 after tillage leading to lower densities under rotary hoeing (150.7 ± 42.5 worms/m<sup>2</sup>) and no tillage (117.3 ± 24.8 worms/m<sup>2</sup>) than under rotary harrowing (340.0 ± 87.4 worms/m<sup>2</sup>) and grubbing (242.7 ± 43.9 worms/m<sup>2</sup>). Time since tillage significantly increased earthworm densities or biomass, and affected soil moisture and temperature. Across sampling dates, earthworm densities correlated positively with soil moisture and negatively with soil temperature; individual earthworm mass increased with increasing time since tillage. It was concluded that reduced tillage in vineyards has little impact on earthworms when applied in spring under dry soil conditions.

Effect of plant spacing and soil application of aldicarb on nitrogen fixation by spring-sown field beans (Vicia faba L.)

1980 ◽  
Vol 94 (1) ◽  
pp. 203-208 ◽  
Author(s):  
J. F. Witty ◽  
R. J. Roughley ◽  
J. M. Day
Keyword(s):  
Vicia Faba ◽  
Plant Density ◽  
Nitrogenase Activity ◽  
Planting Density ◽  
Soil Conditions ◽  
Plant Spacing ◽  
Vicia Faba L ◽  
Dry Soil ◽  
Field Beans ◽  
Second Peak

SummaryVicia faba cv. Minden was precision planted at densities of 12–100 plants/m2 in 1977 and 30–60 plants/m2 in 1978 with and without seed-bed applications of aldicarb (10 kg/ha).Nitrogenase activity per plant decreased significantly with increased plant density but this was compensated for on an area basis by increased numbers of plants. When expressed on the basis of area, nitrogenase activity was higher with closely, than with widely spaced plants both early and late in the season. Irrespective of planting density nitrogenase activity reached a peak during vegetative growth of the plant and a second peak during rapid pod and seed development. In 1977 the second peak was interrupted by very dry soil conditions but later activity increased following rain.Aldicarb consistently increased nitrogenase activity at all harvests after Sitona damage to the nodules was evident. Over this period plots treated with aldicarb had twice the nitrogenase activity of untreated plots in 1977 and 55% more in 1978.

The Influence of Date of Oviposition and Climatic Conditions on Hatching of Camnula pellucida (Scudder) (Orthoptera: Acrididae)

1966 ◽  
Vol 98 (11) ◽  
pp. 1145-1159 ◽  
Author(s):  
R. Pickford
Keyword(s):  
Embryonic Development ◽  
Snow Cover ◽  
Temperature Regime ◽  
Low Temperatures ◽  
Extended Period ◽  
Weather Conditions ◽  
Climatic Conditions ◽  
Soil Conditions ◽  
Soil Temperatures ◽  
Dry Soil

AbstractField and laboratory hatching experiments were conducted from 1960 through 1963 with eggs of Camnula pellucida (Scudder) laid in field cages and collected at fortnightly intervals. Before freeze-up, embryonic development usually reached prediapause level in all eggs laid before the middle of August; these eggs were the first to hatch when incubated in the laboratory or when left in the soil outdoors. Eggs laid later than mid-August showed progressively less embryonic development and consequently hatched later. Viability was highest in eggs laid during the latter half of August; those laid early in the season often suffered from desiccation because of their long exposure to dry soil conditions; those laid towards the end of the season showed declining viability caused, apparently, by low temperatures. The percentage hatch was relatively high in eggs laid before the end of August but declined progressively thereafter; those laid in October rarely hatched. Seasonal hatching patterns were largely dependent upon weather conditions; such patterns were rapidly completed when an extended period of hot, dry weather continued through the hatching period, but often extended intermittently over a month or more when weather was unsettled. The typical diurnal hatching pattern, which also closely followed the temperature regime, commenced in the morning at 0900–1000 hours as soil temperatures exceeded 65°F., rising to a peak about 1100–1200 hours when temperatures reached 85°F., and then generally declined during the afternoon. However, during rapidly changing weather conditions hatching frequently started and stopped as skies cleared and again clouded over. Winter kill occasionally may be an important factor in reducing populations, especially when snow cover is removed by a mid-winter thaw and sub-zero temperatures follow.

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