HYDRAULIC EFFECTS OF PERPENDICULAR WATER APPROACH VELOCITY ON METER GATE FLOW MEASUREMENT

Accurate flow measurement is required to effectively manage water resources. California Senate Bill X7-7 (SB X7-7), legislates this need by requiring agricultural water providers serving areas greater than 25,000 acres to develop an Agricultural Water Management Plan (AWMP) and adopt pricing based at least partly on volumetric water deliveries (DWR, 2009). This study focused on two of the most common flow measurement/flow control devices used in California open channel water conveyance systems: the circular meter gate and the rectangular meter gate. Testing was conducted on three Armco-type (round gates over round discharge pipe) gates measuring 12”, 18”, and 24” and two rectangular gates (rectangular gates over round discharge pipe) measuring 18” and 24”. The three round gates used in the study were the Model 101C produced and provided by Fresno Valve and Castings Incorporated. The two rectangular meter gates were manufactured by Mechanical Associates located in Visalia, California and provided by the San Luis Canal Company located in Dos Palos, California. Testing was conducted in an outdoor laboratory setting at the Irrigation Training and Research Center’s (ITRC) Water Resources Facility at the California Polytechnic State University in San Luis Obispo, California under a variety of flow conditions as experienced in the field in order to: 1) evaluate the effectiveness of these gates as flow measurement devices and determine whether they meet the volumetric accuracy requirements outlined in SB X7-7, 2) develop standards for installation and use that improve flow measurement accuracy, 3) configure more accurate gate rating tables based on updated coefficient of discharge values, and 4) determine if additional gate rating tables are needed for “high” supply channel velocities. The meter gate was set perpendicular to the supply channel. Baseline data was first collected through testing with low supply channel water velocities. Additional testing was then conducted with high supply channel water velocities to analyze the effect on the coefficient of discharge. Based on previous studies it was hypothesized that as the Froude number (FR#) in the supply channel increased (water approach velocity increased), the coefficient of discharge would decrease as a result of an increase in energy needed for the perpendicular velocity transition. Data evaluation, however, indicated no statistically significant effect of water approach velocity on the coefficient of discharge for the 12”, 18” and 24” circular gates or the 18” and 24” rectangular gates at an α-level = 0.01. When operating the gates under recommended conditions relative flow uncertainty was within +/- 5%. This meets the accuracy requirements set by SB X7-7 for turnout flow measurement devices. Based on the results of this study, Cd values do not need to be adjusted for Froude numbers up to 0.35 for any of the studied gates. It should be noted, however, that while most meter gates used will be in conditions where supply channel Froude numbers do not exceed 0.35, further research is needed to study potential effects from Froude numbers exceeding the range found in this study

Receipt from J. M. Thorburn & Co. to Ogden Goelet

https://digitalcommons.salve.edu/ochre-court/1292/thumbnail.jp

The Impact of Parental Young Onset Dementia on Children and Young People’s Educational Careers

The aim of Sikes and Hall’s(2018) study was to discover the impact of having a parent with young onset dementia (YOD) on children or young people’s educational careers by interview 24 subjects among the ages from 6 to 31 years old (Sikes & Hall, 2018). In this paper, the theoretical perspectives will be identified from the perspective of ontology and epistemology. Methodology and methods will also be discussed. Furthermore, evaluating consistency of the relationship between theoretical perspective and the chosen methodology with the methods conducted is also focused on. Finally, the discussion of ethical issues in the study is also an important part of this paper, not only the ones claimed by the author but also the implicit ones should be considerate

Influence of supply-channel velocity on farm delivery meter gate flow measurement

The work presented here is an extension of previous papers that updated the calibration of round (Armco-type) meter gates (three sizes: 0.30, 0.46, and 0.61 m), developed ratings for rectangular gates (two sizes: 0.46 and 0.61 m) on round pipes, and examined errors and uncertainty related to using these devices for water discharge measurement. Previous works examined gate discharge ratings under low supply-channel flow velocity perpendicular to the gate discharge pipeline. Here, additional testing was conducted to test the hypothesis that higher velocities in the supply channel would show decreased meter gate flow compared to the low-velocity ratings, but that the published gate calibration method would still yield accurate flow-rate calculations. All testing was conducted in a test facility with the gate discharge pipe set perpendicular to the supply channel, as is common in field installations. Velocities up to 0.94 m=s (3.1 ft=s) were tested with the smaller gate and 0.66 m=s (2.2 ft=s) for all other gates. These velocities are on the upper end of velocities found in common earthen irrigation canals (and in many lined channels at the farm delivery level) in California. Interestingly, results indicate that the Froude number of the supply-channel flow did not have a statistically significant (at an α-level of 0.01) influence on gate discharge coefficients. Discharge percent error and uncertainty were examined to compare the discharge coefficients presented in the literature to the discharge measured during the testing at different supply-channel velocities. Under recommended operating conditions, the uncertainty was within ±5% without adjustments for supply-channel velocity. This extended work supports earlier recommendations that meter gates can be an accurate flow measurement device for farm water delivery flow measurement if installed and operated correctl

Growth and yield responses to amending the sugarcane monoculture: interactions between break history and nitrogen fertiliser

Experiments were established in the Burdekin Irrigation Area in North Queensland, Australia, to measure whether yield improvements from breaking the sugarcane monoculture or fumigating the soil could be modified by the application of different rates of nitrogen (N) fertiliser. Experiments were conducted in consecutive crop cycles (phase 1, planted 1998; phase 2, planted 2001) using the variety Q117, with the interaction between N applications and rotation histories discussed for the two plant crops. Histories consisted of alternate crop, bare fallow or mixed grass-legume pastures for periods of 42-66 months, compared with continuous cane as plough-out replant without (PORP) or with (PORP-F) soil fumigation. The N strategies involved combinations of N rates (0-180kgN/ha) and application times (at planting, 90 days after planting (DAP) or split between these times) in phase 1 and N rates (0-300kgN/ha) in phase 2. Histories had differing effects on N available to the cane crop and hence on response to N fertiliser. Some combinations of history and N rate were N-limited and strong linear relationships between biomass production or cane yield and crop N content could be developed. Critical N contents for biomass production (R2≤0.93) and fresh-weight cane yield (R2≤0.88) were 1.42 and 0.57kgN/t, respectively. Application of N fertiliser was shown to have significant impacts on both tiller addition and the retention of tillers to produce harvestable stalks. However, the application of fertiliser N had limited (phase 1) or no (phase 2) capacity to provide the quantum of yield response in soil health benefits associated with breaking the sugarcane monoculture. Increasing N application rates above that required to optimise crop yield resulted in significant decreases in sugar content of cane and thus lower sugar yields. Yield increases solely from improved soil health (i.e. exclusive of N response) constituted advantages averaging 15% (phase 1) to 20% (phase 2) compared with PORP. These effects were manifest early in the establishment of primary shoots in the plant crops, although the longevity of these benefits was limited. Replanting cane after a 3-year crop cycle (plant, 1st and 2nd ratoon) on land that had been under pasture, crop, bare fallow or PORP-F histories (phase 2, cycle 2) showed carryover effects of histories on N availability and fertiliser N responsiveness, but limited yield impacts attributable to residual soil health benefits. These results reinforce the importance of crop rotation during breaks between sugarcane cycles to maintain soil health and improve crop productivity

Using individual tracking data to validate the predictions of species distribution models

The authors would like to thank the College of Life Sciences of Aberdeen University and Marine Scotland Science which funded CP's PhD project. Skate tagging experiments were undertaken as part of Scottish Government project SP004. We thank Ian Burrett for help in catching the fish and the other fishermen and anglers who returned tags. We thank José Manuel Gonzalez-Irusta for extracting and making available the environmental layers used as environmental covariates in the environmental suitability modelling procedure. We also thank Jason Matthiopoulos for insightful suggestions on habitat utilization metrics as well as Stephen C.F. Palmer, and three anonymous reviewers for useful suggestions to improve the clarity and quality of the manuscript.Peer reviewedPostprintPostprintPostprintPostprintPostprin