DOCSLIB.ORG

Kaelin, N Et Al 2017 Evaluation Of

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Kaelin, N Et Al 2017 Evaluation Of Evaluation of potential impacts of the Rangitata South Irrigation Scheme on groundwater Report No. R16/3 ISBN 978-0-947507-33-6 (print) 978-0-947507-34-3 (web) Nicola Kaelin Patrick Durney Mark Trewartha June 2017 Evaluation of potential impacts of the Rangitata South Irrigation Scheme on groundwater Report No. R16/3 ISBN 978-0-947507-33-6 (print) 978-0-947507-34-3 (web) Nicola Kaelin Patrick Durney Mark Trewartha June 2017 Name Date Prepared by : Nicola Kaelin March 2017 Patrick Durney Mark Trewartha Reviewed by : Carl Hanson Groundwater Science Manager External review by: Stephen Douglass GHD Approved by: Stefanie Rixecker Director Science Group Report No. R16/3 ISBN 978-0-947507-33-6 (print) 978-0-947507-34-3 (web) 200 Tuam Street PO Box 345 Christchurch 8140 Phone (03) 365 3828 Fax (03) 365 3194 75 Church Street PO Box 550 Timaru 7940 Phone (03) 687 7800 Fax (03) 687 7808 Website: www.ecan.govt.nz Customer Services Phone 0800 324 636 Evaluation of potential impacts of the Rangitata South Irrigation Scheme on groundwater Summary Background: Construction of the Rangitata South Irrigation Scheme (RSIS) began in 2011. By late 2013, the main ponds were being filled and water was being supplied down the main races. The scheme diverts water from the Rangitata River in times of high flow (greater than 110 cubic metres per second) into seven stepped storage ponds located near Arundel. A network of open races supplies water from the storage ponds to farms. Scheme shareholders must have an on-farm storage pond with a minimum capacity of 250 m³ per hectare of irrigated land. The issue: We received reports of flooding in the RSIS area, including a report about a flooded stock underpass in November 2013. We also received reports on other flooding incidents near old river channels such as the Rangitata River middle channel and Kapunatiki Creek. What we did: We undertook a review of groundwater level and quality data collected from wells in the area. We checked for anomalous changes in groundwater quantity and quality and looked at reasons that may have led to the changes we saw. We created a numerical groundwater model to check the viability of our analyses and conclusions. Our assessment considers the RSIS to include the main storage ponds, all races and on-farm storage ponds, and any changes to irrigation practices that have resulted from the scheme. What we found: Following the commissioning of the RSIS scheme, groundwater levels rose near the scheme’s main storage ponds and races as well as near on-farm storage ponds. Groundwater levels in some wells rose to over a metre above previously recorded high levels in the area immediately downgradient of the main storage ponds, but increases were less farther down the plain. At the same time, groundwater nitrate concentrations have decreased in at least one location. We calibrated our numerical model using groundwater level data from wells in the area. Then, we used the calibrated model to simulate the long-term effects of the various components of the RSIS on the area’s groundwater levels. The model indicates that increased recharge from the RSIS could cause groundwater levels to rise by up to 5 m directly beneath the main storage ponds, up to 3 m in the immediate vicinity of the RSIS ponds and main race, and up to 2 m downstream of the ponds and main race in the middle plain. The results show that the observed changes in groundwater levels can reasonably be attributed to the RSIS and associated infrastructure. What it means: We have not identified any other factors that could explain the observed changes in groundwater levels and quality, so we conclude that they were caused by the installation and utilisation of the RSIS. The recently observed flooding and increases in intermittent stream flows are probably also related to the RSIS, though the extent the flooding would have occurred even without the scheme is not known. Groundwater levels may decline somewhat over time as silt settles on the bottom of scheme ponds and races and reducing leakage, but they are unlikely to return to pre-scheme levels. Environment Canterbury Technical Report i Evaluation of potential impacts of the Rangitata South Irrigation Scheme on groundwater ii Environment Canterbury Technical Report Evaluation of potential impacts of the Rangitata South Irrigation Scheme on groundwater Table of contents Summary i 1 Introduction ..................................................................................................... 1 1.1 Background .................................................................................................................... 1 1.2 Study objectives ............................................................................................................. 1 2 Conceptual model ........................................................................................... 3 2.1 Topography and climate ................................................................................................. 3 2.2 Hydrology ....................................................................................................................... 4 2.3 Geology .......................................................................................................................... 7 2.4 Hydrogeology ................................................................................................................. 9 2.4.1 Groundwater flow............................................................................................... 9 2.4.2 Groundwater recharge ..................................................................................... 12 2.4.3 Land use and irrigation .................................................................................... 14 2.4.4 Groundwater use ............................................................................................. 14 3 RSIS construction ......................................................................................... 17 4 Recent observed groundwater trends in the Rangitata South groundwater system ..................................................................................... 22 4.1 Groundwater levels....................................................................................................... 22 4.2 Flooding ........................................................................................................................ 25 4.3 Groundwater quality ..................................................................................................... 31 4.3.1 Groundwater quality trends ............................................................................. 31 5 Numerical modelling .................................................................................... 34 5.1 Introduction ................................................................................................................... 34 5.2 Pre-scheme model ....................................................................................................... 34 5.2.1 Model configuration ......................................................................................... 34 5.2.2 Groundwater recharge and abstraction ........................................................... 36 5.2.3 Surface water sources and sinks ..................................................................... 36 5.2.4 Model calibration.............................................................................................. 37 5.2.5 Calibration results ............................................................................................ 39 5.3 Post-scheme model ...................................................................................................... 39 5.4 Results of modelled scenarios ..................................................................................... 42 6 Discussion .................................................................................................... 44 6.1 Increase in natural recharge ......................................................................................... 44 6.2 Groundwater abstraction .............................................................................................. 46 6.3 Implementation and utilisation of the RSIS .................................................................. 47 7 Conclusions .................................................................................................. 47 8 Recommendations ........................................................................................ 47 Environment Canterbury Technical Report iii Evaluation of potential impacts of the Rangitata South Irrigation Scheme on groundwater 9 Acknowledgements ...................................................................................... 48 10 References .................................................................................................... 49 Appendix A: Groundwater level records for wells in the study area showing signs of increasing groundwater levels ........................................... 53 Appendix B: Groundwater quality records for monitoring wells in the study area 77 Appendix C: MIKE SHE recharge modelling .......................................................... 89 Appendix D: Steady-state MODFLOW model ...................................................... 110 Appendix E: MODFLOW results ........................................................................... 119 Appendix F: Calibration statistics .......................................................................
Load more

Recommended publications
  • Demonstration of GSSHA Hydrology at Goodwin Creek Experimental Watershed by Charles W
    ERDC TN-SWWRP-08-x March 2008 Demonstration of GSSHA Hydrology at Goodwin Creek Experimental Watershed By Charles W. Downer PURPOSE: The purpose of this System-Wide Water Resources (SWWRP) technical note is to describe the application of the Gridded Surface Subsurface Hydrologic Analysis (GSSHA) model at the Goodwin Creek Experimental Watershed (GCEW). The purpose of applying the model at this site was to confirm that the hydrologic portions of the code were working properly and were able to achieve accurate results. Application of GSSHA at this site also allows the current model to be compared and contrasted with the performance of previous versions of the model. BACKGROUND: GSSHA is a physics-based, distributed-parameter, hydrology and transport code. As part of SWWRP, the GSSHA model has undergone a series of major improvements and additions including changes to the stream hydraulics, soil moisture accounting, and sediment transport portions of the model. While these additions and improvements enhance the model’s ability to perform additional analysis, it is essential that the new methods and enhanced model be tested to assure that the model is functioning as desired and that the model can reproduce historic results at an equal or superior level to previous versions of GSSHA. The GCEW, a small (21.2-km2) agricultural watershed located in northeast Mississippi, has been the test bed for many features of the GSSHA model. The watershed is instrumented to measure rainfall, hydrometeorological variables, soil moisture, and stream water and sediment discharge (Figure 1). Legend Streamflow gage with rain gage 6 SCAN Station 9 12 5 8 11 Rain gage 3 10 2 4 7 13 14 Scale (m) 1 1000 0 5001000 N Figure 1.
    [Show full text]
  • Catchment Hydrological Modeling with Soil Thermal Dynamics During Seasonal Freeze-Thaw Cycles
    water Article Catchment Hydrological Modeling with Soil Thermal Dynamics during Seasonal Freeze-Thaw Cycles Nawa Raj Pradhan 1,*, Charles W. Downer 1 and Sergei Marchenko 2 1 Coastal and Hydraulics Laboratory, U.S. Army Engineer Research and Development Center, 3909 Halls Ferry Road, Vicksburg, MS 39180-6199, USA; [email protected] 2 Geophysical Institute, University of Alaska Fairbanks, Fairbanks, AK 99775, USA; [email protected] * Correspondence: [email protected] Received: 16 November 2018; Accepted: 2 January 2019; Published: 10 January 2019 Abstract: To account for the seasonal changes in the soil thermal and hydrological dynamics, the soil moisture state physical process defined by the Richards Equation is integrated with the soil thermal state defined by the numerical model of phase change based on the quasi-linear heat conductive equation. The numerical model of phase change is used to compute a vertical soil temperature profile using the soil moisture information from the Richards solver; the soil moisture numerical model, in turn, uses this temperature and phase, information to update hydraulic conductivities in the vertical soil moisture profile. Long-term simulation results from the test case, a head water sub-catchment at the peak of the Caribou Poker Creek Research Watershed, representing the Alaskan permafrost active region, indicated that freezing temperatures decreases infiltration, increases overland flow and peak discharges by increasing the soil ice content and decaying the soil hydraulic conductivity exponentially. Available observed and the simulated soil temperature comparison analysis showed that the root mean square error for the daily maximum soil temperature at 10-cm depth was 4.7 ◦C, and that for the hourly soil temperature at 90-cm and 300-cm was 0.17 ◦C and 0.14 ◦C, respectively.
    [Show full text]
  • CEN33 CSI Fish & Game Opihi River Flyer
    ACCESS ETIQUETTE • No dogs • No guns Opihi River • No camping • Leave gates as you find them • Stay within the river margins • Do not litter • Respect private property • Avoid disturbing stock or damaging crops • Do not park vehicles in gateways • Be courteous to local landowners and others Remember the reputation of ALL anglers is reflected by your actions FISHING ETIQUETTE • Respect other anglers already on the water • Enquire politely about their fishing plans • Start your angling in the opposite direction • Refer to your current Sports Fishing Guide for fishing regulations and bag limits A successful angler on the Opihi River Pamphlet published in 2005 Central South Island Region Cover Photo: Lower Opihi River upstream of 32 Richard Pearse Drive, PO Box 150, Temuka, New Zealand State Highway 1 Bridge Telephone (03) 615 8400, Facsimile (03) 615 8401 Photography: by G. McClintock Corporate Print, Timaru Central South Island Region THE OPIHI RIVER Chinook salmon migrate into the Opihi River ANGLING INFORMATION usually in February and at this time the fishing pressure in the lower river increases significantly. FISHERY The Opihi River supports good populations of As a result of warm nor-west rain and snow melt both chinook salmon and brown trout. In the The Opihi River rises in a small modified wetland waters from the mouth to about the State of approximately 2 hectares at Burkes Pass and the larger Rakaia and Rangitata Rivers often flood and during these times the spring fed Opihi Highway 1 bridge there is a remnant population flows in an easterly direction for about 80 km to of rainbow trout, survivors of Acclimatisation enter the Pacific Ocean 10 km east of Temuka.
    [Show full text]
  • Christchurch Newspapers Death Notices
    Christchurch Newspapers Death Notices Parliamentarian Merle denigrated whither. Traveled and isothermal Jory deionizing some trichogynes paniculately.so interchangeably! Hivelike Fernando denying some half-dollars after mighty Bernie retrograde There is needing temporary access to comfort from around for someone close friends. Latest weekly Covid-19 rates for various authority areas in England. Many as a life, where three taupo ironman events. But mackenzie later date when death notice start another court. Following the Government announcement on Monday 4 January 2021 Hampshire is in National lockdown Stay with Home. Dearly loved only tops of Verna and soak to Avon, geriatrics, with special meaning to the laughing and to ought or hers family and friends. Several websites such as genealogybank. Websites such that legacy. Interment to smell at Mt View infant in Marton. Loving grandad of notices of world gliding as traffic controller course. Visit junction hotel. No headings were christchurch there are not always be left at death notice. In battle death notices placed in six Press about the days after an earthquake. Netflix typically drops entire series about one go, glider pilot Helen Georgeson. Notify anyone of new comments via email. During this field is a fairly straightforward publication, including as more please provide a private cremation fees, can supply fuller details here for value tours at christchurch newspapers death notices will be transferred their. Loving grandad of death notice on to. Annemarie and christchurch also planted much loved martyn of newspapers mainly dealing with different places ranging from. Dearly loved by all death notice. Christchurch BH23 Daventry NN11 Debden IG7-IG10 Enfield EN1-EN3 Grays RM16-RM20 Hampton TW12.
    [Show full text]
  • Reference Guide 3: Education Records Pupils, Teachers & Schools
    Christchurch Regional Office Reference Guide 3: Education Records Pupils, Teachers & Schools Summary This reference guide gives an overview of the key education records that we hold which contain information about pupils, teachers and schools in Canterbury and Westland; please note that our records relate only to publicly-funded schools. - June 2019 Page 1 of 15 Reference Guide 3: Education Records - Pupils, Teachers & Schools Contents Introduction ............................................................................................................. 2 Access ...................................................................................................................... 3 School Records ......................................................................................................... 3 Introduction ............................................................................................................... 3 List of Schools ............................................................................................................. 4 School Histories .......................................................................................................... 9 Canterbury Association Schools ............................................................................... 10 Teachers ................................................................................................................. 11 Introduction ............................................................................................................
    [Show full text]
  • South Canterbury Artists a Retrospective View 3 February — 11 March, 1990
    v)ileewz cmlnd IO_FFIGIL PROJEEGT South Canterbury Artists A Retrospective View 3 February — 11 March, 1990 Aigantighe Art Gallery In association with South Canterbury Arts Society 759. 993 17 SOU CONTENTS Page LIST OF ILLUSTRATIONS 3 INTRODUCTION 6 BIOGRAPHIES Early South Canterbury Artists 9 South Canterbury Arts Society 1895—1928 18 South Canterbury Arts Society formed 1953 23 South Canterbury Arts Society Present 29 Printmakers 36 Contemporaries 44 CATALOGUE OF WORKS 62 LIST OF ILLUSTRATIONS Page S.C. Arts Society Exhibition 1910 S.C. Arts and Crafts Exhibition 1946 T.S. Cousins Interior cat. I10. 7 11 Rev. J.H. Preston Entrance to Orari Gorge cat. I10. 14 13 Capt. E.F. Temple Hanging Rock cat. 1'10. 25 14 R.M. Waitt Te Weka Street cat. no. 28 15 F.F. Huddlestone Opawa near Albury cat. no. 33 16 A.L. Haylock Wreck of Benvenue and City of Perth cat. no. 35 17 W. Ferrier Caroline Bay cat. no. 36 18 W. Greene The Roadmakers cat. 1'10. 39 2o C.H.T. Sterndale Beech Trees Autumn cat. no. 41 22 D. Darroch Pamir cat. no. 45 24 A.J. Rae Mt Sefton from Mueller Hut cat. no. 7O 36 A.H. McLintock Low Tide Limehouse cat. no. 71 37 B. Cleavin Prime Specimens 1989 cat. no. 73 39 D. Copland Tree of the Mind 1987 cat. 1'10. 74 40 G. Forster Our Land VII 1989 cat. no. 75 42 J. Greig Untitled cat. no. 76 43 A. Deans Back Country Road 1986 cat. no. 77 44 Farrier J.
    [Show full text]
  • Provincial Comparatives Q1 2012
    NIELSEN NATIONAL READERSHIP SURVEY Q1 2012 - Q4 2013 PROVINCIALS – 2 YEAR REPORT ANNOTATIONS Release of Nielsen Consumer and Media Insights Q1 2012 - Q4 2013 – 2 Year Report FURTHER INFORMATION: If you have any questions regarding the Nielsen Consumer and Media Insights Survey report, please contact your Account Manager or the Nielsen Media Helpdesk 0800 457 226. 2 NIELSEN NATIONAL READERSHIP Copyright © 2014 The Nielsen Company 3 PROVINCIAL TOPLINES REPORT NORTHLAND CMI CMI CMI Q1 12 - Q4 13 Q3 11 - Q2 13 Q1 11 - Q4 12 POPULATION POTENTIALS 72 72 72 (TOTAL 15+) [000s]: SAMPLE SIZE (15+): 702 706 686 DAILY NEWSPAPERS (AIR) THE NORTHERN 22 22 22 ADVOCATE 30.4% 30.6% 31.3% 10 10 11 THE NZ HERALD 13.7% 14.3% 15.0% DAILY NEWSPAPERS (WEEKLY COVERAGE) THE NORTHERN 38 41 41 ADVOCATE 52.7% 56.8% 56.9% 20 22 22 THE NZ HERALD 28.3% 31.0% 31.3% COMMUNITY NEWSPAPERS (AIR) 36 38 43 THE WHANGAREI REPORT 49.9% 52.1% 59.8% 36 37 42 WHANGAREI LEADER 50.0% 51.6% 58.8% 4 NIELSEN NATIONAL READERSHIP PROVINCIAL TOPLINES REPORT TAURANGA CMI CMI CMI Q1 12 - Q4 13 Q3 11 - Q2 13 Q1 11 - Q4 12 POPULATION POTENTIALS 127 127 126 (TOTAL 15+) [000s]: SAMPLE SIZE (15+): 965 946 956 DAILY NEWSPAPERS (AIR) 39 42 43 BAY OF PLENTY TIMES 30.7% 33.4% 34.4% 21 21 23 THE NZ HERALD 16.7% 16.8% 18.1% DAILY NEWSPAPERS (WEEKLY COVERAGE) 66 70 73 BAY OF PLENTY TIMES 51.7% 54.9% 57.6% 39 41 44 THE NZ HERALD 31.1% 32.4% 34.8% COMMUNITY NEWSPAPERS (AIR) 55 55 56 BAY NEWS 43.5% 43.6% 44.6% 74 76 73 THE WEEKEND SUN 58.6% 59.8% 58.1% Copyright © 2014 The Nielsen Company 5 PROVINCIAL TOPLINES
    [Show full text]
  • Concepts and Dimensionality in Modeling Unsaturated Water Flow and Solute Transport
    1 Concepts and dimensionality in modeling unsaturated water flow and solute transport J.C. van Dam#, G.H. de Rooij#, M. Heinen## and F. Stagnitti### Abstract Many environmental studies require accurate simulation of water and solute fluxes in the unsaturated zone. This paper evaluates one- and multi-dimensional approaches for soil water flow as well as different spreading mechanisms to model solute behavior at different scales. For quantification of soil water fluxes, Richards’ equation has become the standard. Although current numerical codes show perfect water balances, the calculated soil water fluxes in case of head boundary conditions may depend largely on the method used for spatial averaging of the hydraulic conductivity. Atmospheric boundary conditions, especially in the case of phreatic groundwater levels fluctuating above and below a soil surface, require sophisticated solutions to ensure convergence. Concepts for flow in soils with macropores and unstable wetting fronts are still in development. One-dimensional flow models are formulated to work with lumped parameters in order to account for the soil heterogeneity and preferential flow. They can be used at temporal and spatial scales that are of interest to water managers and policymakers. Multi-dimensional flow models are hampered by data and computation requirements. Their main strength is detailed analysis of typical multi-dimensional flow problems, including soil heterogeneity and preferential flow. Three physically based solute-transport concepts have been proposed to describe solute spreading during unsaturated flow: The stochastic-convective model (SCM), the convection-dispersion equation (CDE), and the fractional advection-dispersion equation (FADE). A less physical concept is the continuous-time random-walk process (CTRW).
    [Show full text]
  • Publications
    PUBLICATIONS Water Resources Research RESEARCH ARTICLE A new general 1-D vadose zone flow solution method 10.1002/2015WR017126 Fred L. Ogden1, Wencong Lai1, Robert C. Steinke1, Jianting Zhu1, Cary A. Talbot2, and John L. Wilson3 Key Points: 1 2 We have found a new solution of the Department of Civil and Architectural Engineering, University of Wyoming, Laramie, Wyoming, USA, Coastal and general unsaturated zone flow Hydraulics Laboratory, Engineer Research and Development Center, U.S. Army Corps of Engineers, Vicksburg, Mississippi, problem USA, 3Department of Earth and Environmental Science, New Mexico Tech, Socorro, New Mexico, USA The new solution is a set of ordinary differential equations Numerically simple method is guaranteed to converge and to Abstract We have developed an alternative to the one-dimensional partial differential equation (PDE) conserve mass attributed to Richards’ (1931) that describes unsaturated porous media flow in homogeneous soil layers. Our solution is a set of three ordinary differential equations (ODEs) derived from unsaturated flux and mass Correspondence to: conservation principles. We used a hodograph transformation, the Method of Lines, and a finite water- F. L. Ogden, content discretization to produce ODEs that accurately simulate infiltration, falling slugs, and groundwater [email protected] table dynamic effects on vadose zone fluxes. This formulation, which we refer to as "finite water-content" simulates sharp fronts, and is guaranteed to conserve mass using a finite-volume solution. Our ODE solution Citation: Ogden, F. L., W. Lai, R. C. Steinke, method is explicitly integrable, does not require iterations and therefore has no convergence limits and is J. Zhu, C.
    [Show full text]
  • The Glacial Sequences in the Rangitata and Ashburton Valleys, South Island, New Zealand
    ERRATA p. 10, 1.17 for tufts read tuffs p. 68, 1.12 insert the following: c) Meltwater Channel Deposit Member. This member has been mapped at a single locality along the western margin of the Mesopotamia basin. Remnants of seven one-sided meltwater channels are preserved " p. 80, 1.24 should read: "The exposure occurs beneath a small area of undulating ablation moraine." p. 84, 1.17-18 should rea.d: "In the valley of Boundary stream " p. 123, 1.3 insert the following: " landforms of successive ice fluctuations is not continuous over sufficiently large areas." p. 162, 1.6 for patter read pattern p. 166, 1.27 insert the following: " in chapter 11 (p. 95)." p. 175, 1.18 should read: "At 0.3 km to the north is abel t of ablation moraine " p. 194, 1.28 should read: " ... the Burnham Formation extends 2.5 km we(3twards II THE GLACIAL SEQUENCES IN THE RANGITATA AND ASHBURTON VALLEYS, SOUTH ISLAND, NEW ZEALAND A thesis submitted in fulfilment of the requirements for the Degree of Doctor of Philosophy in Geography in the University of Canterbury by M.C.G. Mabin -7 University of Canterbury 1980 i Frontispiece: "YE HORRIBYLE GLACIERS" (Butler 1862) "THE CLYDE GLACIER: Main source Alexander Turnbull Library of the River Clyde (Rangitata)". wellington, N.Z. John Gully, watercolour 44x62 cm. Painted from an ink and water­ colour sketch by J. von Haast. This painting shows the Clyde Glacier in March 1861. It has reached an advanced position just inside the remnant of a slightly older latero-terminal moraine ridge that is visible to the left of the small figure in the middle ground.
    [Show full text]
  • Daily Newspapers
    10 The Northern Advocate (N) Daily Newspapers Whangārei Published: Morning Mon-Sat Page size: Compact Mon-Fri 1 The New Zealand Herald (N) Broadsheet Sat Auckland Published: Morning Mon-Sat 11 Bay of Plenty Times (N) Page size: Compact Mon-Fri Tauranga Broadsheet Sat Published: Morning Mon-Sat Page size: Compact Mon-Fri 2 Waikato Times (S) Broadsheet Sat Hamilton Published: Morning Mon-Sat 12 Whakātane Beacon (I) Page size: Compact Mon-Fri Whakātane Broadsheet Sat Published: Morning Wed & Fri 10 Page size: Compact 3 Taranaki Daily News (S) New Plymouth 13 Rotorua Daily Post (N) Published: Morning Mon-Sat Rotorua Page size: Compact Mon-Fri 1 Published: Morning Mon-Sat Broadsheet Sat Page size: Compact Mon-Fri Broadsheet Sat 4 Whanganui Chronicle (N) Whanganui 14 The Gisborne Herald (I) Gisborne Published: Morning Mon-Sat 2 Page size: Compact Mon-Fri 11 12 Published: Afternoon Mon-Sat Broadsheet Sat Page size: Compact 5 Manawatū Standard (S) 14 15 Wairoa Star (I) Palmerston North 13 Wairoa Published: Morning Mon-Sat Published: Morning Tues & Thu Page size: Compact Mon-Fri 15 Page size: Compact Broadsheet Sat 3 16 Hawkes Bay Today (N) 6 Wairarapa Times Age (I) 16 Hastings Masterton Published: Morning Mon-Sat Published: Morning Mon-Sat Page size: Compact Mon-Fri Page size: Compact 4 Broadsheet Sat 7 The Dominion Post (S) 5 17 The Westport News (I) Wellington Westport Published: Morning Mon-Sat Published: Afternoon Mon-Fri Page size: Compact Mon-Fri 6 Page size: Broadsheet Broadsheet Sat 18 Greymouth Star (I) 8 The Nelson Mail (S) 7 Greymouth
    [Show full text]
  • Richards' Equation: Transition Between Constitutive Equations
    Journal of Advanced Research in Applied Mechanics 73, Issue 1 (2020) 11-19 Journal of Advanced Research in Applied Mechanics Journal homepage: www.akademiabaru.com/aram.html ISSN: 2289-7895 Richards’ Equation: Transition Between Constitutive Equations and the Mechanics of Water Flow in Unsaturated Open Access Soil Sunny Goh Eng Giap1,*, Noborio Kosuke2 1 Faculty of Ocean Engineering Technology and Informatics, Universiti Malaysia Terengganu, 21030 Kuala Terengganu, Terengganu, Malaysia 2 Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki 214-8571, Japan ABSTRACT Water flow in soil is normally governed by Richards’ partial differential equation. Similarly, the equation can be used to investigate water infiltration in the soil. It is well understood that when water hits the surface of the topsoil, it infiltrates into the soil. However, the mechanics behind the infiltration of water is unknown to many researchers. This study aims to reveal the mechanics behind the well-known Richards’ equation that has been used enormously in governing water flow in unsaturated soil since 1931. A classic case study of Haverkamp’s water infiltration into Yolo Light Clay was used in the study. The Richards’ equation has been discretized using finite difference method and the algebraic solution has been coded into Simply Fortran 2008. The partial differential equation of Richards is supported by two constitutive functions. The functions from Haverkamp and van Genuchten were compared. It is often for researcher to change between the hydraulic functions, which have limitation on the simulation outcome. The solution to overcome the limitation by changing the constitutive function variables was provided. Keywords: water flow in soil; unsaturated soil; water flux; water adsorption Copyright © 2020 PENERBIT AKADEMIA BARU - All rights reserved 1.
    [Show full text]