Grass species selection to control for concentrated flow erosion in grassed waterways.

2020 ◽  
Author(s):  
Corina Lees ◽  
Robert Simmons ◽  
Jane Rickson
Keyword(s):  
Flow Rate ◽  
Water Depth ◽  
Water Samples ◽  
Performance Indicators ◽  
Bare Soil ◽  
Grass Species ◽  
Concentrated Flow ◽  
Below Ground ◽  
Experimental Treatments ◽  
Grass Sward

<p>Grassed waterways reduce water runoff, prevent scouring and encourage sediment deposition from erosion prone land. The aim of this study was to assess the efficacy of conventional and novel grass species (as monocultures and mixtures) to control erosion, at an early establishment stage (6 weeks), within grassed waterways. The experimental treatments included bare soil (B), a conventional mix of Lolium perenne and Festuca rubra (C), Festulolium cv prior (F1), Festulolium cv prior and Festulolium bx511 (F1+F2), and all grass species combined (F1+F2+C). F1 is adapted to flooded conditions, whilst F2 is adapted to drought conditions. With climate change in the UK likely to result in drier summers and wetter winters these Festulolium species will be adapted to future climatic conditions. However, little is known about their efficacy within grassed waterways. The grasses were established in 1.2 x 1 x 0.5m macrocosms in a sandy clay loam soil during June-Aug, 2019. A sub sample of each experimental treatment was taken (0.3 x 0.1 x 0.1m) from the macrocosms within a stainless steel box. Tests were replicated in quadruplicate.<br>The following above ground trait (Stem area density) and the following below ground traits (Total root length of fine roots <0.25mm, root diameter and root surface area) were determined for each experimental replicate. Prior to testing, the grass was cut to circa 3.0 cm height to represent a mowed grass sward before being placed into a fully instrumented hydraulic flume. The hydraulic flume simulated a concentrated flow event and treatment performance was assessed in terms of turbidity, sediment concentration, soil loss and flow velocity.<br>The effects of roots+shoots and of roots only on performance indicators were determined to quantify the relative contribution of above ground vs below ground traits in controlling erosion. One set of replicates was tested only with roots whilst another set of replicates was tested with roots+shoots and then with roots only. This was done to isolate the effect of below ground and above ground traits.<br>All replicates were subjected to a concentrated flow event with increasing incremental flow velocities from 0.2-0.6l s-1 for bare soil, 0.2-0.8l s-1 for roots+shoots treatments and 0.2-1.4l s-1 for roots only treatments. Each flow rate velocity was run for 60 seconds. For each flow rate, duplicate water samples were taken downslope of the treatment and water depth was measured, upstream of the treatment, in the centre of the treatment and downstream of the treatment.  The water samples were used to determine sediment concentrations. The water depth measurements were used to determine runoff velocity. Furthermore, a turbidity meter continuously measured turbidity during the concentrated flow event. Soil detachment and transport rates were significantly reduced for all experimental treatments as compared to the bare soil (p<0.05). Final treatment efficacy will be assessed based on a ranking of the key performance indicators. The knowledge gained from this research can be used and applied to other grassed soil erosion mitigation features such as in field and riparian buffer strips, swales as well as grassed waterways.</p><p> </p>

scholarly journals PERUBAHAN KECEPATAN ALIRAN AKIBAT VARIASI VOLUME VEGETASI DI BELOKAN SALURAN IRIGASI

2019 ◽  
Vol 2 (2) ◽  
pp. 114-122
Author(s):  
Muhammad Nasir ◽  
Eldina Fatimah ◽  
Masimin Masimin
Keyword(s):  
Energy Loss ◽  
Flow Rate ◽  
Water Depth ◽  
Local Community ◽  
Secondary Channel ◽  
Flow Area ◽  
Turn Angle ◽  
Irrigation Network ◽  
Speed Distribution ◽  
North Sumatra

D. I Timbang Deli is 520 Ha of flow area and 5000 meters of secondary channel is located in Deli Serdang Regency, North Sumatra Province. The turn of the irrigation network in overgrown vegetation on the cliffs and bottom of the channel, is expected to reduce the flow rate. The purpose of the study was to see the distribution of velocity, resistance and energy loss in the secondary channel due to vegetation. The method used is conducting surveys in the field by measuring water depth, vegetation volume and flow velocity. Trapezoidal channel with 36 m length, 1.45 lower width, 3.15 m upper width and 33,510 turn angle. The velocity measured in the middle and downstream regions across the channel is divided from points X1 to X5 with Q1 = 0.62m3/ sec and Q2 = 0.83 m3/sec. The results obtained in the speed distribution in Q1 Vmax mean X1 = 0.296 m/s and X5 = 0.199 m/s, the speed decreases due to the turn of 48.82%. On VV3 Vmaks the average is X4 = 0.216 m/sec and (X1 and X2) = 0,000 m/sec, the volocity decreases due to the presence of vegetation between X1, X2 and X5 at Q1 = 100%. In Q2 the average VV0 Vmax condition of the flow X1 = 0.477 m/s and X5 = 0.323 m/s between X1 and X5 the volocity decreases due to turn 28.45%. VV3 Vmax conditions on average X5 = 0.312 m / s and X1 = 0.000 m / s, between X1 and X5 the speed decreases due to the presence of 100% vegetation. In connection with the above results, with this research the local community and local government can carry out cleaning on the channel on a scale basis.

scholarly journals RESTORATION OF FORMER GRASSLAND IN SOUTH-CENTRAL TEXAS

2019 ◽  
Vol 71 (1) ◽  
Author(s):  
Wendy J. Leonard ◽  
O. W. Van Auken
Keyword(s):  
San Antonio ◽  
Plant Cover ◽  
Woody Species ◽  
Bare Soil ◽  
Grass Species ◽  
Herbaceous Plant ◽  
Percent Cover ◽  
Juniperus Ashei ◽  
South Central ◽  
Central Texas

Abstract In the past, grasslands and savannas were common in many areas of south-central Texas, including the San Antonio area. With the advent of European settlers and their livestock, much of this area was converted to agriculture and rangeland. Today, most of San Antonio is developed, but some preservation has occurred. Restored grassland, mechanically cleared of Juniperus ashei (juniper, Ashe juniper) and other woody species in 2013, was examined and compared to adjacent non-cleared woodland. The woodland examined was dominated by Diospyros texana (Texas persimmon) and Juniperus ashei. Richness in the woodland canopy was 15 species. The understory below the canopy had 25 woody species. In the restored grassland area, herbaceous plant cover was 41.8%, woody plant cover 5.8%, bare soil 2.9%, and litter cover 49.5%. Species richness was 71, with 60 herbaceous and 11 woody species (percent cover of each from <0.1–7.1%). The most common species in the restored grassland in descending order were Nassella leucotricha (Texas winter grass), Calyptocarpus vialis (straggler daisy), Carex planostachys (cedar sedge), Sporobolus crypandrus (sand dropseed), D. texana, and Verbesina virginica (frost weed). Several C4 grass species were present with low cover but may increase in abundance over time. Four of the six most common restored grassland species were present below the woodland canopy and 12 woody species were present in the restored grassland as juveniles. Cost of restoration was approximately $38,500 ($7,500 supplies, $31,000 labor).

scholarly journals Effects of Post-Fire Deadwood Management on Soil Macroarthropod Communities

Forests ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 1046 ◽  
Author(s):  
Carlos R. Molinas-González ◽  
Jorge Castro ◽  
Adela González-Megías ◽  
Alexandro B. Leverkus
Keyword(s):  
Sierra Nevada ◽  
Dead Wood ◽  
Management Strategies ◽  
Bare Soil ◽  
Ecosystem Functions ◽  
Higher Plant ◽  
Salvage Logging ◽  
Management Interventions ◽  
Biological Legacies ◽  
Experimental Treatments

Dead wood comprises a vast amount of biological legacies that set the scene for ecological regeneration after wildfires, yet its removal is the most frequent management strategy worldwide. Soil-dwelling organisms are conspicuous, and they provide essential ecosystem functions, but their possible affection by different post-fire management strategies has so far been neglected. We analyzed the abundance, richness, and composition of belowground macroarthropod communities under two contrasting dead-wood management regimes after a large wildfire in the Sierra Nevada Natural and National Park (Southeast Spain). Two plots at different elevation were established, each containing three replicates of two experimental treatments: partial cut, where trees were cut and their branches lopped off and left over the ground, and salvage logging, where all the trees were cut, logs were piled, branches were mechanically masticated, and slash was spread on the ground. Ten years after the application of the treatments, soil cores were extracted from two types of microhabitat created by these treatments: bare-soil (in both treatments) and under-logs (in the partial cut treatment only). Soil macroarthropod assemblages were dominated by Hemiptera and Hymenoptera (mostly ants) and were more abundant and richer in the lowest plot. The differences between dead-wood treatments were most evident at the scale of management interventions: abundance and richness were lowest after salvage logging, even under similar microhabitats (bare-soil). However, there were no significant differences between microhabitat types on abundance and richness within the partial cut treatment. Higher abundance and richness in the partial cut treatment likely resulted from higher resource availability and higher plant diversity after natural regeneration. Our results suggest that belowground macroarthropod communities are sensitive to the manipulation of dead-wood legacies and that management through salvage logging could reduce soil macroarthropod recuperation compared to other treatments with less intense management even a decade after application.

scholarly journals Effects of mycorrhizal inoculant, N:P supply ratio, and water depth on the growth and biomass allocation of three wetland plant species

2005 ◽  
Vol 83 (9) ◽  
pp. 1117-1125 ◽  
Author(s):  
Lauchlan H. Fraser ◽  
Larry M. Feinstein
Keyword(s):  
Biomass Allocation ◽  
Water Depth ◽  
Soil Surface ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Nutrient Supply ◽  
Wetland Plant ◽  
Below Ground ◽  
Root:Shoot Ratios ◽  
Water Depths

In the greenhouse, we investigated the growth and biomass allocation of three juvenile wetland species ( Carex tribuloides Wahl., Phalaris arundinacea L., and Rumex orbiculatus Gray) under three different water depths (–4, 0, and +2 cm relative to the soil surface), three N:P supply ratios (1:30, 1:1, 30:1), and two mycorrhizal inoculant treatments (arbuscular mycorrhizal (AM) fungi present, absent). After 6 weeks, the plants were harvested, separated to above- and below-ground parts, oven-dried, and weighed. The mycorrhizal inoculant significantly increased plant growth and reduced root:shoot ratios. At an N:P supply ratio of 30:1, plants with AM fungi had significantly greater biomass than those plants without AM fungi. However, at 1:1 N:P supply ratio, plants without AM fungi had greater biomass. Plants without AM fungi had higher root:shoot ratios at 0 and –4 cm water depth than plants with AM fungi. In general, C. tribuloides had the lowest growth, and unlike P. arundinacea and R. orbiculatus, was not affected by the water depth treatment. Growth of the wetland plants was limited more by nitrogen than by phosphorus. Our results suggest that at high N:P nutrient supply ratios and non-flooded conditions the growth of wetland seedlings can benefit by being inoculated with AM fungi.

Effect of two forest grasses differing in their growth dynamics on the water relations and the growth of Quercus petraea seedlings

1996 ◽  
Vol 74 (10) ◽  
pp. 1562-1571 ◽  
Author(s):  
Catherine Collet ◽  
Henri Frochot ◽  
Jean-Marc Guehl ◽  
André Ferhi
Keyword(s):  
Water Stress ◽  
Carbon Isotope ◽  
Isotope Composition ◽  
Soil Water Potential ◽  
Bare Soil ◽  
Quercus Petraea ◽  
Grass Species ◽  
Basal Diameter ◽  
Root Interactions ◽  
Intrinsic Water Use Efficiency

Interference between 1-year-old sessile oak (Quercus petraea (Mattus.) Liebl.) seedlings and two grass species (Agrostis stolonifera L. and Deschampsia cespitosa (L.) Beauv.) was evaluated during 3 years after seedling transplantation. The seedlings were grown in large containers under crossed levels of watering regimes (regular irrigation that maintained the soil at field capacity or seasonal water stress) and grass competition (with Agrostis, Deschampsia, or bare soil). After 3 years, seedling basal diameter was 2.5 times greater in the absence of competing vegetation than with one of the two grasses. Within the grass-competition treatments, diameter was 1.3 times as great for the seedlings grown in the irrigated treatments than for the seedlings grown in the water-stressed treatments and was 1.3 times greater for the seedlings grown with Agrostis than for the seedlings grown with Deschampsia. During the first 2 years, the seedlings grew much faster in the bare soil than in the weedy treatments, whatever the watering level. During the 3rd year, the seedlings in all the irrigated treatments showed similar relative growth rate values, which were much higher than those in the water-stressed treatments. Each year, soil water potential reached −2.5 MPa under the two grasses and −0.7 MPa under bare soil by the end of summer. On the contrary, competition for nutrients seemed to be low. Assessments of plant carbon isotope composition showed that the seedlings in the weedy water-stressed treatments had higher intrinsic water-use efficiency, and also suggested that the competition exerted by the two grasses occurred mainly for water. We conclude that during the first 2 years, the negative effects of the two grass species on seedling growth seemed to be largely independent of any competition for water. Conversely, during the 3rd year, the influence of the grasses on the seedlings seemed to be related only to competition for water. Keywords: root interactions, water stress, osmotic adjustment, carbon isotope discrimination, classical growth analysis.

Impact of Electronic Faucets and Water Quality on the Occurrence ofPseudomonas aeruginosain Water: A Multi-Hospital Study

2014 ◽  
Vol 36 (3) ◽  
pp. 311-319 ◽  
Author(s):  
Dominique Charron ◽  
Emilie Bédard ◽  
Cindy Lalancette ◽  
Céline Laferrière ◽  
Michèle Prévost
Keyword(s):  
Water Quality ◽  
Flow Rate ◽  
Water Samples ◽  
Cold Water ◽  
Residual Chlorine ◽  
Increased Risk ◽  
High Concentrations ◽  
Enzymatic Detection ◽  
Enzyme Detection ◽  
Hospital Study

OBJECTIVETo comparePseudomonas aeruginosaprevalence in electronic and manual faucets and assess the influence of connecting pipes and water quality.SETTINGFaucets in 4 healthcare centers in Quebec, Canada.METHODSWater samples from 105 electronic, 90 manual, and 14 foot-operated faucets were analyzed forP. aeruginosaby culture and enzymatic detection, and swab samples from drains and aerators were analyzed by culture. Copper and residual chlorine concentrations, temperature, and flow rate were measured.P. aeruginosaconcentrations were analyzed in 4 consecutive volumes of cold water and a laboratory study was conducted on copper pipes and flexible hoses.RESULTSP. aeruginosacontamination was found in drains more frequently (51%) than in aerators (1%) or water (culture: 4%, enzyme detection: 16%). Prevalence in water samples was comparable between manual (14%) and 2 types of electronic faucets (16%) while higher for foot-operated faucets (29%). However, type 2 electronic faucets were more often contaminated (31%) than type 1 (14%), suggesting that faucet architecture and mitigated volume (30 mL vs 10 mL) influenceP. aeruginosagrowth. Concentrations were 100 times higher in the first 250 mL than after flushing. Flexible hoses were more favorable toP. aeruginosagrowth than copper and a temperature of 40°C led to higher counts.CONCLUSIONSThe types of faucets and connecting pipes, flow rate, and water quality are important parameters influencing the prevalence and the concentrations ofP. aeruginosain faucets. High concentrations ofP. aeruginosain the first 250 mL suggest increased risk of exposure when using the first flush.Infect Control Hosp Epidemiol 2014;00(0): 1–9

scholarly journals Cadmium in Water Samples determined by Atomic Absorption Spectrometry after Solid Phase Extraction using DOWEX 50WX2 resin

2021 ◽  
Vol 6 (1) ◽  
pp. 14-19
Author(s):  
Yuniar Yuniar ◽  
◽  
Siti Nuraini
Keyword(s):  
Detection Limit ◽  
Solid Phase Extraction ◽  
Atomic Absorption Spectrometry ◽  
Flow Rate ◽  
Water Samples ◽  
Solid Phase ◽  
Tap Water ◽  
Absorption Spectrometry ◽  
Phase Extraction ◽  
Optimum Conditions

The Pre-concentration of Cd(II) in water samples was carried out by using column solid phase extraction DOWEX 50WX2 prior to flame atomic absorption spectrometry analyzed. The analytical parameters consist of pH, flow rate, volume of eluent and volume of sample were determined.The optimum conditions were obtained pH was 5, sample flow rate was 1 mL min−1, volume of eluent nitric acid 1N was 10 mL and sample volume was 50 mL. The optimum conditions obtained were used to determine the detection limit and the accuracy of the method using tap water samples. Determination of detection limit used tap water which contain Cd 0.001 mg L-1 and the accuracy (recovery,%R) with concentration of Cd 0.01 mg L-1. The detection limit was found 0.2697±0.0899 µg L− 1 (n=7) and accuracy (n=7) was 93±6%. The result showed the accuracy still meets the acceptance criteria for accuracy (70%-125%) and the RSD 6% is smaller than the Horwitz value of 20.8%. Based on the accuracy (R%) and % RSD values obtained, it can be concluded that this method provides effective results for pre-concentration to increase the detection limit of Cd (II)in clean water using SSA-flame.

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