Applications of Geosynthetics to Irrigation, Drainage and

APPLICATIONS OF GEOSYNTHETICS TO IRRIGATION, DRAINAGE ANDAGRICULTURE†

ERIC BLOND1, STAN BOYLE2, MARIANNA FERRARA3, BRUNO HERLIN4, HERVE PLUSQUELLEC5,PIETRO RIMOLDI6* and TIMOTHY STARK7

1Consultant, Montreal, Québec, Canada2Shannon & Wilson, Inc., Seattle, Washington, USA

3Maccaferri Mexico, Queretaro, Mexico4terrafix Geosynthetics Inc., Toronto, Ontario, Canada

5Consultant, Washington D.C., USA6Civil Engineering Consultant, Milano, Italy

7University of Illinois at Urbana-Champaign, USA

ABSTRACT

Geosynthetics are man-made products manufactured to meet specific functions in earthworks and geotechnical projects, suchas dams, levees, canals, dikes and other structures commonly found in agricultural engineering. Thanks to the Memorandum ofUnderstanding between the International Geosynthetics Society (IGS) and the International Commission on Irrigation andDrainage (ICID), collaborative efforts are being undertaken to generate awareness of geosynthetics in agriculture. In theWorkshop on ‘Applications of geosynthetics to irrigation, drainage and agriculture’ held at the 23rd International Congressof the ICID in Mexico City on 8 October 2017, a group of delegates from the IGS contributed with a series of presentationsintroducing various functions and applications of geosynthetics. The authors gave an overview of how geosynthetic productsare designed and tested to ensure they will fulfil their intended function, focusing on applications to irrigation, drainage andagriculture. A few key considerations were identified as being critical to ensure proper performance of geosynthetic materials,in geotechnical projects in general and in agriculture in particular. The present paper is intended to provide a summary of thesepresentations. © 2018 John Wiley & Sons, Ltd.

key words: geosynthetics; irrigation; drainage; reinforcement; waterproofing; erosion control; agriculture

Received 8 April 2018; Revised 21 August 2018; Accepted 22 August 2018

RÉSUMÉ

Les géosynthétiques sont des produits artificiels fabriqués pour répondre à des fonctions spécifiques dans des projets deterrassement et de géotechnique, tels que des barrages, des levées, des canaux, des digues et d’autres structures courammentutilisées en ingénierie agricole. Grâce au Mémorandum d’accord entre la Société Internationale des Géosynthétiques (IGS)et la Commission Internationale sur l’Irrigation et le Drainage (CIID), des efforts de collaboration sont en cours poursensibiliser le public aux géosynthétiques en agriculture. Lors de l’atelier sur les « applications des géosynthétiques àl’irrigation, au drainage et à l’agriculture » qui s’est tenu à Mexico le 23 octobre 2017, un groupe de délégués de l’IGS aprésenté une série de présentations portant sur les diverses fonctions et applications des géosynthétiques. Les auteurs ont donnéun bref aperçu de la façon dont les produits géosynthétiques sont conçus et testés pour s’assurer qu’ils rempliront leur fonctionprévue, en se concentrant sur les applications à l’irrigation, au drainage et à l’agriculture. Quelques considérations clés ont étéidentifiées comme étant critiques pour assurer la bonne performance des matériaux géosynthétiques dans les projetsgéotechniques en général et dans l’agriculture en particulier. Le présent document vise à fournir un résumé de ces présenta-tions. © 2018 John Wiley & Sons, Ltd.

mots clés: géosynthétiques; irrigation; drainage; renforcement; imperméabilisation; contrôle de l’érosion; agriculture

*Correspondence to: Pietro Rimoldi, Civil Engineering Consultant, Corso Garibaldi 125, 20121 Milano, Italy. Tel.: +39–329-6949120. E-mail: [email protected]†Applications de la géosynthétique à l’irrigation, au drainage et a l’agriculture.

IRRIGATION AND DRAINAGE

Irrig. and Drain. (2018)

Published online in Wiley Online Library (wileyonlinelibrary.com) DOI: 10.1002/ird.2300

© 2018 John Wiley & Sons, Ltd.

INTRODUCTION

Geosynthetics are polymeric materials. The most commonlyused polymers are polyethylene, polypropylene and polyes-ter. There are also other polymers used in lining material,such as PVC, EPDM and CSPE, each product offering prop-erties which may be particularly attractive in specific envi-ronmental conditions. There are many grades available foreach of these polymers, and many additives can be used tocontrol how a polymer reacts to a given environment.

Geosynthetics are man-made products manufactured tomeet specific functions in earthworks and geotechnical pro-jects, such as dams, levees, canals, dikes and other structurescommonly found in agricultural engineering. This industryhas experienced a growth in the range of 10% per year sincethe first products were successfully installed back in theearly 1970s, to become a well-structured industry with overUS$5 billion annual sales. Geosynthetics are identified inmany countries as a ‘must’, with stringent regulatory re-quirements defining their usage in transportation as well asenvironmental applications. In the USA, they are consideredone of the few emerging materials permitting a sustainableapproach to construction. This was formally acknowledgedin 2014, when the US Army Corps of Engineers (USACE)was instructed through the Water Resources Reform andDevelopment Act (WRRDA) to consider ‘durable, resilient,and sustainable materials and practices, including the use ofgeosynthetics, advanced composites, and innovative tech-nologies’ (Section 3021).

To facilitate education of potential users, the industryhas created a scientific and technical society, the Interna-tional Geosynthetics Society (IGS). The IGS is an interna-tional non-profit organization as is the InternationalCommission on Irrigation and Drainage (ICID). IGShas now over 4000 members and over 160 corporatemembers in 44 National Chapters, and is dedicated tothe scientific and engineering development of geotextiles,geomembranes, related products and associated technolo-gies. It offers technical guidance and other informationrelated to geosynthetics, in particular through its web page(geosyntheticssociety.org).

With cost-effectiveness, low environmental impact andquantifiable performance, geosynthetic materials are hereto stay and will be classified as ‘another standard construc-tion material’ for future generations, just like concrete,steel, masonry and wood are today. A discussion on howgeosynthetics can contribute to sustainable developmentwas developed as a video by the IGS and can be found onthe IGS website.

Thanks to the Memorandum of Understanding signedbetween the IGS and the ICID at the 21st international Con-gress held in Teheran in 2011, collaborative efforts are beingundertaken by the IGS and the ICID to generate awareness

of geosynthetics in agriculture. Part of this is the Workshopon ‘Applications of geosynthetics to irrigation, drainage andagriculture’ held at the 23rd International Congress of theICID in Mexico City on 8 October 2017, where a group ofdelegates from the IGS contributed with a series of presenta-tions introducing various functions and applications ofgeosynthetics. The workshop was introduced first duringthe Plenary Session by Herve Plusquellec with a focus onthe risk of failures of canals lined with rigid materials undercertain environment conditions. The authors’ presentationsincluded an overview of how geosynthetics are designedand tested to ensure they will fulfil their intended function,focusing on testing aspects and availability of standards. Afew key considerations were identified as being critical toensure proper performance of geosynthetic materials, ingeotechnical projects in general and in agriculture in partic-ular. The present paper is intended to provide a summary ofthese presentations.

GLOBAL WATER ISSUES, CANAL LINING ANDGEOSYNTHETICS

Global water issues, such as increasing water scarcity, waterproductivity, food security and environment have been themain themes and topics of questions of ICID Congressesduring the last two decades. The move from engineering toglobal development issues reflects the vision of ICID.However, a balanced attention to technical and institutionalsolutions is needed to solve present deficiencies in design,construction, operation and management of irrigation sys-tems. Innovation is a priority in some economic sectorsand it should be the same in irrigation. Despite that liningof canals accounts for about 40–60% of the total cost ofrehabilitation and modernization projects today, the lasttime canal lining was one of the Questions of an ICIDCongress was at the 1957 Congress held in San Francisco.The IGS workshop in Mexico City offered an opportunityto attendees to learn about the principles of geosyntheticsapplications for irrigation canals, reservoirs and flood man-agement covering the functions of water containment andbarriers, conveyance, reinforcement, stabilization and ero-sion control. Testing of geosynthetics was also addressed.Advanced yet well-proven technologies exist to solve prob-lems in irrigation system design and construction. The keyissue is the adaptation and adoption of these techniques.

Geosynthetics are used to solve difficult engineeringproblems, including sealing of hydraulics works, slope sta-bility and erosion control. Geosynthetics are consideredthe most important innovation in geotechnical and environ-mental engineering in the last 50 years. Geosyntheticsmaterials have a considerable potential use in agriculture,which remains to be developed, notably in irrigation canalsystems.

2 E. BLOND ET AL.

© 2018 John Wiley & Sons, Ltd. Irrig. and Drain. (2018)

Geosynthetics include a number of categories:geomembranes, geotextiles, geogrids, geonets, geocells,geomats, etc., and the combination of these products intogeocomposites.

The first significant applications of geosynthetics incivil engineering date back about 60 years ago. Drainagespecialists are familiar with the use of geotextiles.Geosynthetics are widely used in dam engineering. Damsof all types, gravity and arch dams, rockfill and earth damshave been waterproofed through the use of geosynthetics.Geomembranes, 2 or 3 mm thick, have been used in the con-struction of new dams and rehabilitation of dams up to200 m high. In agriculture, exposed geomembranes arewidely used worldwide for the lining of canals, and reser-voirs and farm ponds that store water for irrigation.

Today there are so many new and original scientificadvances in many fields, such as transportation and commu-nications, that anyone from two generations ago would becompletely disoriented. However, an engineer of the 1950swould not be disoriented visiting many irrigation systemsin use today. Driving along irrigation canals today engineerswould observe unlined and concrete-lined canals, very likethe ones designed in the 1950s. Only new to this engineerwould be control centres equipped with remote monitoringand remote control of automated gates in some advancedirrigation schemes. Moving to the farms, they would beimpressed by the adoption of water-saving techniques bythe farmers. However, the irrigation community at largehas been slow in adopting modern techniques to improvethe efficiency and operation of surface irrigation systems.

The most typical solution has been to line canals withrigid materials such as masonry, brick, cast-in-situ concreteor pre-cast concrete panels. Indeed some rigid canal liningsbuilt with high-quality standards of construction still per-form well decades later. However, experience has demon-strated that under certain climatic and/or soil conditionsrigid lining may lose its waterproofing functionality withina short period of time and in the most serious cases the con-crete lining loses its structural integrity.

Billions of dollars have been spent to line canals, but alarge part of investment in canal lining has been a waste ofmoney. Water losses through a moderately cracked concretelining or with leaking joints are close to the losses from anunlined canal. Numerical models have demonstrated thatlinings with small imperfections result in a small reductionof seepage losses compared to an unlined canal.

There is considerable evidence of the failures of concreterigid canal lining (Figure 1). Cement concrete is a watertightmaterial. Water losses would be negligible if it was not forthe danger of cracking. Concrete has a good compressivestrength but a low tensile strength. It is a rigid material thatadapts poorly to ground deformation no matter how small itis. Hard surface linings could deteriorate within a few yearsuntil seepage returns to what it was in an unlined canal. Thecause of ineffectiveness of concrete canal lining over time isrelated to the quality of its construction and to the physics ofseepage flow lines. Saturation of the soils caused by seepagethrough joints and cracks causes some settlement of thesubbase of side slopes resulting in a separation betweenthe subbase and concrete. The concrete slabs eventuallywould rest on just a few points, thus resulting in develop-ment of cracks in the slab.

Furthermore, many irrigation projects worldwide, for ex-ample those located around the latitudes of about 35–55°inthe northern hemisphere, are affected by frequent freezingand thawing resulting in dislocation of pre-cast panels orcast-in-situ concrete slabs and ultimately in their slide intothe bottom of canals and by the disintegration of concrete.The effect of a cold climate is further aggravated by the siltynature of the soils. Regions greatly affected are the provincesof Inner Mongolia and Xinjiang in China, the central Asiacountries, and the Caucasian region (for example Armenia).

Despite the possible poor performance of rigid lining,some irrigation agencies continue to adhere to the designstandards for canal lining and have been averse to the adop-tion of modern canal lining which would use flexible mate-rials available with the progress in the contemporarygeosynthetics industry. This situation exists because many

Figure 1. Examples of failures of concrete canal lining.

3GEOSYNTHETICS FOR IRRIGATION AND DRAINAGE


engineers are familiar with concrete linings and because, tothem, ‘hard’ is preferable to ‘flexible’. The engineers anddecision-makers who prefer cement concrete linings wouldhave to be better aware of the deterioration of cement con-crete linings over time.

The reasons for the slow adoption of modern canal-liningtechniques are both administrative and behavioural: resis-tance to change by irrigation departments; risk aversionand adherence to outdated designs; lack of contractual moti-vation for consultants to introduce new technology; lack ofsufficient information about proven new technologies bythe consultants, and, in some cases, failures of pilot projectsresulting in a long period before piloting again proven tech-nologies but unknown in a particular country.

Lining canals with geomembranes is no longer a simpleplacement of a plastic film as it was the case in the earlyyears. There are a number of technical issues to beaddressed such as the stability of the composite lining overthe side slopes, the selection of the type and thickness ofgeomembranes, drag forces exerted by flowing water ongeosynthetics and uplift of geomembranes by dynamicpressures.

Stronger is not better. Flexibility of the geomembrane andits capacity to conform to the variances in profile of the sub-base of the canals are essential.

Geosynthetics, including geomembranes, are widely usedto solve engineering problems in many sectors of civil engi-neering such as transportation (highways, railways), envi-ronmental engineering (e.g. waste storage landfills), miningapplications (heap leach pads, tailings dams) and hydraulicengineering (dams, reservoirs). Clearly, geosynthetics havepervaded all branches of geotechnical engineering. The samecan happen with irrigation canals. Indeed, there is a widepotential for applications of geomembranes and othergeosynthetics throughout the field of irrigation with over250 million ha of lands worldwide irrigated with canals,many of which need rehabilitation.

GEOMEMBRANES FOR IRRIGATION CANALS,RESERVOIRS AND FLOOD MANAGEMENT

Fresh water is a precious resource with demands rising dailyand supply greatly fluctuating. Leakage and evaporationfrom irrigation canals, ponds and reservoirs represent a sig-nificant loss of this important resource for agricultural andfood production. Only 2% of all water on Earth is freshwater with 98% being salt water. This 2% of fresh water iscomprised of: 87% ice, 12% groundwater and 1% riversand lakes. Thus, only 13% of the available fresh water isreadily accessible for agricultural, domestic and industrialuses, so protecting this small amount of fresh water is highlyimportant.

At present, irrigation accounts for 70% of all freshwaterusage. Industrial and domestic uses account for the remain-ing 22 and 8%, respectively. The demand for fresh water isalso increasingly significant in developing countries so thereis an increasing need to protect fresh water in these coun-tries. A current example is Cape Town, South Africa, whichis facing a complete water shortage. By 2025, the percentageincrease in water usage and withdrawals will be 50% in de-veloping countries but only 18% in developed countries.This reinforces the objective of protecting freshwater re-sources in developing countries. This includes minimizingleakage and water loss from irrigation canals, ponds and res-ervoirs through seepage into the underlying soils and/orevaporation and presenting contamination.

Given fresh water is a scarce resource, it is also impera-tive that it not only be captured and held for use but that itis also protected from surface and subsurface contaminationsources. Containment basins/reservoirs are used in manyapplications for storing, processing and recycling in indus-tries like oil and gas, wastewater, raw water, industrial pro-cesses, agriculture and recreation. These containment basinsand reservoirs would need to use low hydraulic conductivityliner systems to achieve one of the following two basicobjectives: (i) hold fresh water and prevent leakage or evap-oration, or (ii) protect fresh water from contamination.

Liner systems

These low hydraulic conductivity liner systems can be madeof concrete, bitumen, soil with amendments, compactedfine-grained soils, e.g. clay, or geosynthetics. Each of theseliner system materials have differing levels of hydraulicconductivity, construction complexity and cost, so choosingthe right liner system material would have to be based onimpermeability, constructability, durability and overallvalue. In developing countries, it is usually not practicalto source natural materials and the costs of traditionalmaterials, like concrete, bitumen and soil amendments, areusually prohibitive. As a result, geosynthetics represent acost-effective solution for protecting valuable fresh waterin developing countries. Geomembranes create a physicalbarrier, which prevents water from leaking into the underly-ing soils and/or evaporating by forming a cover over thecanal, pond or reservoir. Geomembranes (Figure 2) are thinsheets made of high-density polyethylene (HDPE), PVC orother polymers, usually supplied in rolls, which have to bebonded on site to provide continuity of waterproofing.

The focus here is therefore the use of geomembranes tominimize leakage and water loss from irrigation canals,ponds and reservoirs into the underlying soils and/or evapo-ration. Geosynthetics have been important innovations incivil and environmental engineering in the last 50 years,

4 E. BLOND ET AL.


and are getting wider and wider use in the fields of irriga-tion, drainage and agriculture.

Geomembrane liners are more effective than soil liners inminimizing leakage and water loss from irrigation canals,ponds and reservoirs. For example, Table I compares thesaturated hydraulic conductivity of various soils and itshows that clays exhibit the lowest values for the range ofsoils shown. Table I also shows an intact geomembrane isat least 1000 times less permeable than clayey soils.

Lining of irrigation canals

Geomembranes have been used as water canal liners tocontrol seepage since the 1950s (Figure 3) and are an effec-tive alternative to more traditional lining methods, such asconcrete and compacted soil (Stark and Hynes, 2009).One of the first uses of a geomembrane for a water canalwas in 1954 for a US Bureau of Reclamation (USBR) irriga-tion canal near Fort Collins, Colorado. The flexibility ofgeomembranes allows them to conform to the canal sub-grade without puncturing and to adapt to subgrade changeswith time. Geomembranes are also less pervious than con-crete and compacted soil, allowing for less loss of waterover time. However, geomembranes are susceptible to dam-age from environmental and mechanical factors so variousprotective coverings have been used. Mechanical damagemeans damage to the geomembrane caused by people,

animals and/or equipment, whereas environmental damagerefers to ultraviolet, wind, precipitation, etc. damage.

The USBR has extensive experience in the installationand monitoring of geomembranes for canal liners based onfield test programmes. The first such test programme wasstarted with a PVC test section on the Shoshone Project inWyoming in 1957 (Morrison and Comer, 1995). The USBRinstalled geomembrane linings in other canals and in 1991began a canal-lining demonstration project on various canalsbranching from the Deschutes River (Swihart and Haynes,2002). The Deschutes Canal-Lining Demonstration Projectis comprised of 34 test sections in Oregon, Idaho, Montanaand Oklahoma and was initiated to evaluate the effective-ness of a range of canal-lining alternatives.

Traditionally, PVC geomembranes have been thegeomembrane used for canal-lining projects. However, re-cently polyethylene (PE)-based geomembranes (HDPE,LDPE, CSPE and VLDPE) as well as several other typesof geomembranes (e.g. EDPM and polypropylene) havebeen used as canal liners.

All geomembranes are susceptible to damage from sun,wind, wave action, vegetation roots and animal traffic, andthus must be protected. The most traditional method ofprotecting a geomembrane is to cover it with compactedsoil. Another method is to cover the liner with concrete orshotcrete. The last option is to not protect the geomembraneand leave it exposed. Such exposed geomembranes may re-quire special treatment and consideration to prevent damage.

Case history: Arnold Irrigation District—Main Canal—Bend, Oregon

The Arnold Main Canal (Stark and Hynes, 2009) is locatedseveral kilometres south of Bend, Oregon, and divertswater from the Deschutes River about 11 km to the east.On average the canal is 20 m wide, 3 m deep and has a flowcapacity of about 4 m3 s�1. The subgrade along the ArnoldMain Canal consists primarily of fractured basaltic rock anda sandy–silty sediment. Subgrade preparation beforegeomembrane installation included the removal of loose

Figure 2. Physical aspect and available dimensions for typical geomembranes.

Table I. Comparison of hydraulic conductivities of soils andgeosynthetics

Soil type Saturated hydraulicconductivity (m s‾¹)

Gravel 10�2 to 1Sand 10�5 to 10�2

Silt 10�8 to 10�5

Clay 10�11 to 10�8

Geosynthetic clay liners (GCLs) 10�11 to 10�10

Intact geomembranes 10�14 to 10�13



rocks, boulders and overhangs. Certain sections of thecanal subgrade were also covered with 2–5 cm of soilcushion before placing the geomembrane. Canal-liningsystems installed along the Arnold Main Canal include a0.10 mm thick polyethylene (PE) geomembrane with ashotcrete cover, a 0.75 mm thick VLDPE geomembranewith a shotcrete cover, an exposed 2.0 mm thickHDPE geomembrane, an exposed 0.25 mm thick PVCgeomembrane, a 1.0 mm thick PVC geomembrane witha grout mattress cover, and exposed 1.5 mm thick HDPEand VLDPE geomembranes. In short, a variety ofgeomembranes were tested in a similar environment,which provides for a meaningful comparison of effective-ness and durability. All of the geomembranes with ageotextile cover or cushion exhibit adequate seepage re-duction, i.e. greater than 90%.

Pond leakage calculator

The Pond Leakage Calculator (Stark, 2017) is a MicrosoftExcel spreadsheet based on Darcy’s law of seepage or flowthrough porous media. The Pond Leakage Calculator com-putes the leakage rates from a canal, pond or reservoirconstructed or lined with a compacted clay liner and ageomembrane. The Pond Leakage Calculator allows theuser to input the size of the containment basin (includinglength, width, depth, side slope angle and freeboard), the an-ticipated level of hydraulic conductivity of the liner systemmaterial (from Table I), and the relative cost of water interms of 1 acre foot (1233 m3) of water. The Calculatorthen computes the leakage and cost savings of using ageomembrane over a compacted clay liner system for

containing the volume of water needed for the application.In particular, the Calculator calculates the volume of thebasin in gallons (4.546 litres), leakage rates through thecompacted soil and geomembrane liner systems in gallons,and the cost of the leakage based on the cost of water peracre-foot to replace it. The Calculator can also be used tosize a pond or canal to transmit a certain volume of water.This spreadsheet tool is designed to help consultants, engi-neers, architects and end users to decide how to line canals,ponds, reservoirs and basins to capture and/or protect freshwater. The example presented in Figure 4 shows that theuse of geomembranes can decrease the water loss from apond by a factor of over 4000 when compared to compactedsoil liner.

The range of liner systems that are used for water contain-ment applications is: (i) native soil, usually least desirable;(ii) compacted fine-grained soil (clay); (iii) geomembraneoverlaying native soils; (iv) composite liner system, i.e.geomembrane overlying compacted fine-grained soil; (v)an enhanced composite liner system with a geomembraneunderlain by a geosynthetic drainage layer and native orcompacted fine-grained soil. The calculation in Figure 4shows that installing a geomembrane over native soils in de-veloping countries results in significant protection of freshwater and a lower cost than other liner system materials.

Case history: Prospect Lake in Colorado

Prospect Lake has been a landmark in Colorado Spring,Colorado, and used for a variety of applications (Starket al., 2005). However, the estimated annual water lossdue to seepage into the sandy and permeable foundation

Figure 3. Examples of irrigation canals lined with geomembranes.

6 E. BLOND ET AL.


soils (Figure 5) was very high: Prospect Lake is 21.5 ha (53acres) in size and loses about 265 000 m3 (215 acre-feet) ofwater per year, which was not sustainable because there isno natural recharge for the lake.

There was insufficient soil to construct a compacted claybarrier on the lake bottom so a geomembrane placed overthe native soils was recommended. A 0.75 mm (30 mil)thick PVC geomembrane was selected because it could befactory fabricated into panels (Figure 6) and seamed in thefield, which reduced field installation time and costs. Over-lying the PVC geomembrane is a 270 g m�2 (8 oz per squareyard) cushion non-woven geotextile and 0.3 m of cover soilfrom the lake bottom.

The geomembrane was fabricated into 113 PVCgeomembrane panels, each 21.3 m by 91.5 m (70 ft by300 ft), which resulted in fabricating about 0.25 millionm2 (2.4 million square ft) of geomembrane panels. This re-sulted in 109.1 km (64.2 miles) of factory seams being cre-ated instead of in the field, which resulted in higher-qualityseams. Because the majority of the geomembrane seamswere created in the factory, only 13.4 km (7.9 miles) of fieldseams had to be created (Figure 7). In other words, onlyabout 10% of the total seams had to be created in the field.All of the field seams were tested by inflating the air channel

and requiring the air channel pressure to be held for a spec-ified time. To date this is the largest use of air-channel test-ing for PVC geomembranes in the USA. Figure 8 shows therefilled lake, which has been performing well since comple-tion in 2005.

GEOSYNTHETIC CLAY LINERS

ISO 10318–1 (2015) norm defines a clay geosynthetic bar-rier (GBR-C), also known as a geosynthetic clay liner(GCL), as a ‘factory-assembled structure of geosyntheticmaterials in the form of a sheet in which the barrier functionis essentially fulfilled by clay’. In practice, a GCL consistsof bentonite clay or other very low permeability materials,supported by geotextiles and/or geomembranes which areheld together by needling, stitching or chemical adhesives.

There are many types of GCLs (Figure 9): stitched,glued, needle-punched, with different bentonite contents,different types of bentonite (sodium-based bentonites ver-sus calcium-based activated bentonites), and differentgeotextiles types and weights.

The clay component, when hydrated, becomes a gel withvery low permeability, of the order of 10�11 m s�1. It is

Figure 4. Example of calculation with the Pond Leakage Calculator (Stark, 2017).



important to consider that a confining pressure, of the orderof few kPa, is required for the clay to acquire low permeabil-ity during the hydration process. Such pressure can be pro-vided by simply covering the GCL with a layer of soil ofappropriate thickness.

Since the late 1980s, GCLs have been specified and usedby design engineers, agencies and owners as an alternativeto soil barriers in various applications. The growing interestin these products stems from the properties and advantages

they offer. They are effective as a hydraulic barrier even un-der high gradient conditions; they are easy to install; show arobustness against installation stresses, and can withstandelongation as well as settlement stresses without significantimpact on their hydraulic performance; they afford the prop-erty of self-healing when a cut or hole is produced. The widerange of GCL use includes landfill caps and base liner appli-cations, environmental protection barriers under roads andrailways, waterproofing of buildings and structures, and

Figure 6. Large PVC geomembrane panels were unfolded and deployed to cover large areas of the lake bed.

Figure 5. Sandy and permeable lake subgrade after draining of the lake water.

8 E. BLOND ET AL.


various containment structures such as dams, canals, ponds,rivers and lakes. GCLs have been largely used for water-proofing of irrigation ponds (Figure 10). Numerous labora-tory studies have shown the excellent performance of

natural sodium bentonite geosynthetic clay liners. In morerecent years, field conditions have been replicated in large-scale simulations to study the complex environmentaleffects such as wet/dry and freeze/thaw cycles as well asionic exchange. Research and field installations during thelast three decades have shown that GCLs are equal if notsuperior to compacted clay liners.

GCLs in pond applications and/or any type of hydraulichead conditions should always contain a woven geotextileor woven – nonwoven composite to provide resistanceto tensile stresses. Some GCLs contain synthetic coatingsto decrease the permeability of the GCL to the range of ageomembrane.

GCLs in pond applications should always be coveredwith a minimum of 300 mm of soil. If used in slopes greaterthan 3(H) : 1(V) one needs to consider adding an enhancedpolymer to the bentonite to ensure permeability is achieved,while the confining stress over the GCL (provided by thecover soil) needs to be designed to achieve the desired lowpermeability.

Simple, cost-effective installation techniques make GCLsa practical alternative to compacted clay liners or other lin-ing systems. GCLs do not require an experienced installa-tion contractor and can be installed by local generalcontractors and/or local crews.

GEOSYNTHETIC REINFORCEMENT FOR IRRI-GATION CANAL EMBANKMENTS

Incorporating geosynthetic reinforcement in irrigation canalembankments is a proven and effective means to reduceconstruction and maintenance costs and improve embank-ment performance.

Figure 7. Non-woven cushion geotextile being deployed over two fabricated PVC geomembrane panels being welded together.

Figure 8. Prospect Lake project completed, with the lake refilled with water.



Geosynthetic reinforcement consists of geogrids orgeotextile sheets that are incorporated at the base of andwithin embankments to aid in construction, reduce poten-tial for foundation failure and excessive deformation, facil-itate embankment construction on sloping ground, andconstruct steeper embankment slopes than might otherwisebe possible.

When used below access roads, geosynthetic reinforce-ment separates the roadway aggregate from the foundationsoil, avoiding mixing of the materials that can lead to in-creased fill volumes, reductions in strength of the roadwayaggregate, and rutting. The tensile resistance provided bythe geosynthetic reinforcement decreases degradation ofthe roadway foundation under traffic loads. The combinedseparation and reinforcement functions of the geosyntheticimproves roadway performance, reduces initial roadwayconstruction costs (less aggregate is required) and reducesmaintenance costs and frequency (reduced rutting), asshown in Figure 11.

Irrigation canal embankments frequently have to be con-structed across soft and compressible ground, with potentialcanal embankment failures (Figure 12). Geosynthetic

reinforcement placed at the bottom of the canal embankmentimproves stability and may reduce the width of the embank-ment (Figure 13), thereby reducing foundation preparationand embankment soil volumes.

Irrigation canals frequently have to be constructed acrosshillslopes. The natural soil conditions, steepness of the hill-side, weight of the canal embankment, and water leakingfrom the canal into the embankment can decrease embank-ment stability (Figure 14). Geosynthetic reinforcement canbe incorporated in the embankment to improve stability(Figures 15 and 16). Depending on site conditions, multiplelayers of reinforcement might be used to reinforce theembankment slope, which could permit the embankmentslope to be steepened, thereby reducing the foundationarea to be prepared and the volume of fill in the embank-ment. The reduced land area required, reduced fill materialcosts and increased embankment reliability provided by in-clusion of geosynthetic reinforcement make incorporatinggeosynthetics a logical and economical choice.

The cost, schedule and risk reduction benefits providedby using geosynthetic reinforcement have resulted in theseproducts being used for more than four decades to improve

Figure 9. Schemes of different types of GCL and picture showing the hydrated bentonite clay.

Figure 10. GCLs allow waterproofing of irrigation ponds with fast construction and low costs.

10 E. BLOND ET AL.


stability of roadways, embankments and fills constructed onsloping ground. Engineering design procedures and con-struction methods are well established for these geosyntheticreinforcement applications. The geosynthetic reinforcementproducts are engineered and manufactured to established

international standards. Thus, irrigation system owners andoperators are expected to have confidence that geosyntheticreinforcement has the potential to provide them withanother technique for improving their system’s value andreliability.

Figure 11. Geosynthetic reinforcement below construction access and irrigation system maintenance roads support repetitive passes of heavy equipment withreduced maintenance needs.

Figure 12. Potential canal embankment failure when embankment is constructed on soft ground.

Figure 13. Canal embankment failure prevented by using geosynthetic basal reinforcement. Tension that develops in the reinforcement (horizontal yellowarrows) provides necessary stability.

Figure 14. Potential failure of irrigation canal embankment when a canal is constructed on a hillside.



EROSION CONTROL ON IRRIGATION CANALSAND AGRICULTURAL SLOPES

Erosion control is one of the biggest challenges in irrigationcanals and for soil conservation of cropped fields within theagricultural sector.

Soil erosion is a form of soil degradation; it refers to theremoval of soil from fields, slopes or canal banks, due tonatural forces like water and wind combined with humanactivities. Erosion is characterized by a three-phase process,starting from soil detachment followed by movement andfinally by deposition. Soil loss can occur at different ratesdepending on important factors such as climate, vegetation,characteristics of soil and topography. The amount andintensity of rainfall are the main governing factors of soilerosion by water. Also temperature may affect erosion be-cause of its effects on soil properties and vegetation. Vege-tation can be considered a physical barrier which coversthe soil and protects it against erosion. The composition,compaction and moisture of soil may have a major impacton the effects of surface runoff, as well as the length, steep-ness and roughness of the slopes. Human activities, such asovergrazing, overcropping, deforestation and constructioncan further increase the rates of soil loss.

Soil erosion can cause several problems including de-crease of agricultural productivity, desertification, sedimen-tation and eutrophication of waterways, and damage to civilinfrastructure. It is then important to control erosion andminimize soil loss.

Among the existing solutions for erosion control,geosynthetics are an effective option. Geosynthetics createa physical barrier which may absorb the impact of waterand wind on soil, resulting in the prevention of soil lossand enhancing of vegetation growth. These products areflexible and environmentally friendly; installation is easyand fast and they can be applied directly on slopes and alongriver and canal banks. The main geosynthetics for erosioncontrol are geomats or biomats (Figure 17). Metallicgeosynthetics for erosion control include double-twistedwire mesh gabions and mattresses.

Biomats are made of natural fibres, which are kept to-gether by natural or synthetic low-weight meshes. Biomatscan absorb a high amount of water and, during theirnatural degradation, can produce nutritious materials forthe vegetation.

Geomats are made of synthetic filaments tangled togetherto form a deformable layer 10–20 mm thick, with high po-rosity. There is also a reinforced version of geomats: it isproduced by joining a geomat and a geogrid or a metallicmesh in factory. The reinforcement increases the tensilestrength of the geomat so that it can be used on long andsteep slopes, along the banks of canals and river courseswith relatively high water velocities, where high tensilestrength is required.

Reinforced geomats with metallic mesh have typically atensile strength of 50 kN m�1, while with geogrid reinforce-ment the tensile strength is usually in the range 30–300 kNm�1. The geomat can be made of polypropylene,

Figure 15. The tensile strength provided by geosynthetic reinforcement can prevent foundation failure of an embankment constructed on a hillside and allowsteepening of the embankment slope.

Figure 16. Geogrid reinforcement of a canal embankment with steepened slopes.

12 E. BLOND ET AL.


polyethylene or polyamide filaments, while the reinforce-ment is a double-twisted polymeric coated steel woven wiremesh or an extruded or woven geogrid. This product is flex-ible and easy to install, it gives a strong protection againsterosion and promotes vegetation growth. Reinforcedgeomats can also be used as pre-vegetated blankets; this in-teresting technique consists in pre-vegetating erosion blan-kets and then transporting them to the site for installation.Reinforcement geomats are particularly suitable to the scopeas their high-resistance steel wire mesh or geogrid core al-lows them to be lifted and transported without damagingthe cortical layer of roots.

Other solutions for erosion control, especially in irrigationcanals, involve double twisted wire mesh products such asgabions and mattresses. These solutions are usually imple-mented when high water flow velocity occurs and high shearstresses are applied to canal banks. These products aremanufactured by assembling in factory different doubletwisted wire mesh panels to form boxes of different sizesthat, once on the job site, can be filled with rocks of a spe-cific grade.

Mattresses are flat units which can be used as bank pro-tection, irrigation canal linings or dams. These elementsare always installed in combination with a non-wovengeotextile which, with its filtration function, guarantees fur-ther erosion protection of fine particles of soil. When rocksare not available on the job site or nearby, it is possible to

internally line a mattress with a nonwoven geotextile and fillit with vegetative soil and cover it with a geomat to promoterapid vegetation (Figure 18).

KEY ASPECTS OF GEOSYNTHETIC DESIGNAND SPECIFICATION

First consideration: Design by function

Although geosynthetic materials are all synthetic products,they all are designed to fulfil specific functions, and offerspecific properties which must be selected to meet engineer-ing needs defined by a given project, that is, geotechnicalconditions prevailing where they are to be installed, includ-ing type of soil, water, weather, etc. Geosynthetics canoffer many functions, from filtration and drainage, to water-proofing, going through soil stabilization and reinforcementor erosion control. Obviously, the engineering requirementswhich apply to a particular function do not apply to others.In geosynthetics, there is no such a thing as ‘one size fitsall’. For example, a geotextile must remain permeable overthe course of its life, while a geomembrane must remainimpervious to provide the sealing function it is intended todeliver. Each geosynthetic is primarily defined by the func-tion, or functions, it is intended to deliver to a structure.

How is one to assess that a geosynthetic effectively offersa given function? After five decades of existence, the

Figure 17. Examples of geosynthetics for erosion control. From left to right: geomat; steel mesh reinforced geomat; geogrid reinforced geomat; biomat.

Figure 18. Canal banks protected against erosion with mattresses and reinforced geomats.



geosynthetic industry has developed an array of normativetools, i.e. ASTM, ISO and other standards. These documentsdefine precisely material properties which can be correlatedto engineering needs. A geosynthetic product is only definedby the specification sheet that describes it. In contrast tosoils, which are bulky materials, for which the thickness isa key component of the design, geosynthetics have an insig-nificant thickness, leaving everything to the manufacturingparameters that define the engineering properties that willdefine its properties, thus its capability to deliver a givenfunction.

Second consideration: Ensuring performance first re-quires the product to be delivered and installed

Before the performance of geosynthetics after installation ischallenged, the geosynthetics must be in good conditionwhen they reach the project where they are intended to beused. To address this, standards were developed, coveringthis first critical step of their life, such as ASTM D4873 on‘Identification, storage and handling of geosynthetic mate-rials’. Simple rules are provided regarding identification ofthe product, on-site storage and manipulation of the rollsin a way that will ensure preservation of their properties un-til their function is requested.

Then, the geotextiles must survive installation. This issueis influenced by construction practices, type of equipmentused to lay, and then to cover the products by the granularlayer that comes on top of it, when applicable. Given thelack of scientific information available to quantify thesestresses, different approaches were used to define minimumrequirements that can be considered to ensure survivabilityof the products.

For permeable materials such as geotextiles, AASHTOM288 (2006) is often considered a good guidance for deter-mining minimum properties of geotextile products used intransportation applications. It is based on experimentalobservation of the performance of several different gradesof geotextiles, installed with different types of equipment.It essentially consists of three mechanical properties (tensile,puncture and tear resistance), defined by ASTM and ISOstandards, for which minimum requirements are proposed.

For impermeable materials such as geomembranes, sur-vivability is typically performance-based. With the installa-tion done by certified installers, watertightness of theinstallation is assessed with leak detection programmes,conducted on-site, based on a series of ASTM standardsdedicated to this function. Some tests can be performed im-mediately after lay-off and welding of the products, othersare designed to be performed after soil covering, as thelining system is about ready to be delivered and put infunction.

Third consideration: Functional performance

We can now assume that the products can be delivered tothe project, and installed in order to perform as they areintended to. However, we still have to consider the engineer-ing, functional performance of these products—whichis their primary reason for being installed. There is a sub-stantial literature on this topic: as geosynthetics aremanufactured to meet specific functional requirements, it isobvious that the first thing that is done by each and everymanufacturer developing geosynthetic materials is to definewhat these performance requirements are and to generate avalue that has to be met by the product brought to the mar-ket. The next sections discuss a few performance require-ments applicable to the two main types of geosyntheticmaterials used in agricultural projects, which are lining ma-terials, and geotextile filters.

DESIGN AND TESTING OF GEOSYNTHETICSPRODUCTS USED IN IRRIGATION, DRAINAGE

AND AGRICULTURAL APPLICATIONS

Part 1: Lining materials (geomembranes)

The water permeability of a geomembrane is several ordersof magnitude lower than the permeability of any soil, in-cluding the most ‘impervious’ soil such as montmorillonite.What can be the performance requirement that can be de-fined for such a product? In agricultural engineering as inmost fields of application of geomembranes, the answer liesin the interaction between the geomembrane and the soilsurrounding it. Geomembranes are not designed accordingto their permeability, since they are practically impermeable.They must be designed to stay impermeable, and to avoidunwanted interaction with the structure. To ensure thelong-term sustainability of the design, geomembranes willoften be installed in conjunction with other geosynthetics,such as geotextiles and/or geosynthetic clay liners (GCLs).One can thus describe the performance of a ‘lining system’,more than a ‘geomembrane’!

The most common issues which are considered while de-signing such a lining system are:

• veneer stability. The surface between a geomembraneand the soil or another geosynthetic (i.e. a geotextilecushion) typically affords a lower friction resistancethan the soil intrinsic friction properties. In otherwords, should slippage occur, it is more than likely totake place in the vicinity of or in the lining system.Again, there is sufficient science describing the behav-iour and performance of lining systems. There areASTM and ISO standard test methods dedicated tothe determination of the interface friction properties

14 E. BLOND ET AL.


of the components of the lining system, which can thenbe used to design relevant components of the project,such as the angle of the slopes;

• hydrostatic puncture resistance. The watertightnessshall not be endangered when the lining system is ex-posed to a stress applied through the adjacent material.Most of this task consists of selecting an appropriatecushioning material, typically a geotextile, when thegeomembrane itself is not able to sustain this stress.Theoretical approaches are available to performsuch designs, as well as performance tests such asASTM D5514 (2018). Examples of the response of dif-ferent geomembrane materials to hydrostatic puncturestress are shown in Figure 19. One can note in thesephotos that the geomembrane has adhered to the gravel,and despite it experiencing large local deformations, ithas preserved its integrity and does not present anypuncture, thus it does not leak. This, in fact, reflectsone of the key strategic assets of geosynthetic liningsystems: their capability to sustain minor deformationwithout cracking, tearing or puncturing;

• canal embankments, earth dams and other hydraulicstructures are likely to experience settlement becauseof the consolidation of the subgrade. This could gener-ate differential settlement issues, and thus imposedeformation of the lining system. Only two materialscan maintain their performance when exposed to(reasonable) settlement: clayey liners, assuming thepermeability of clay is low enough to permit its usageas a lining material, and geosynthetic barriers, thanksto their high deformability.

Part 2: Geosynthetic filters (geotextiles)

Filters are necessary to avoid internal erosion of a soil. Ex-cessive internal erosion could create cavities (should the en-tire soil matrix be eroded) or create changes of permeability(should only the fine fraction be transported) that could affectthe stability of a structure, or endanger the performance of adrainage system. To perform well, filters must at the sametime retain the particles of the soil matrix of which could

endanger the stability of the structure, and remain permeable.Their openings must be small enough to retain the soil ma-trix, but large enough to let the water pass through freely.Geotextile filters must, and have proven to do, all this whenproperly designed, with a thickness of a few millimetres.

The functional performance of geotextile filters can beguaranteed only if, as indicated above, its openings are smallenough to retain the soil matrix, and its permeability largeenough to let the water flow freely through its plane. Toperform well, decades of research have proven that thegeotextile must act as a ‘catalyst’, and retain only the coars-est fraction of the soil to be filtered. A ‘self-filtering struc-ture’ develops, which ensures long-term performance ofthe filtering layer as it is basically the soil that filters itself,thanks to the help of the geotextile.

Performance of geotextiles for filtration applicationsis well documented. Geotextile filter design criteria areavailable; they offer a relation between the particle size dis-tribution of the soil and an ‘opening size’ of the filter, aswell as between the permeability of the soil and that of thegeotextile filter. Intrinsic properties of the geotextile (open-ing size and permeability) are defined by ASTM, ISO orother standard test methods. However, should a soil beknown for being exceptionally challenging, it is alsopossible to perform a filtration test per ASTM D5101 - 12(2017), which will expose the soil–geotextile system to themost critical hydraulic conditions and assess experimentallythe suitability of a geotextile for a particular soil and antici-pated service conditions.

Fourth consideration: Long-term durability. How longdo geosynthetics last?

In practice, geosynthetics are designed to be used in soils, toexperience challenging weather, and, for some of them, toresist harsh chemical environments, such as landfills andmining or industrial operations. Some studies haveexpressed durability in multiples of centuries, which maybe valid in some ideal conditions, but very optimistic inothers. Modern polymer science gives very precise guidanceon how to assess the durability of a polymeric material, andthe ‘truth’ lies in the particular service condition applicable

(a) bituminous geomembrane (c) PVC geomembrane(b) HDPE geomembrane

Figure 19. Performance of three different types of geomembrane in contact with a coarse gravel layer as tested per ASTM D5514.



to each project, and of course the formulation of each mate-rial. With standard products meeting standard specifications(i.e. GRI GM13 (2016) for geomembranes, AASHTOM288(2006) for geotextiles), it is safe to consider that ageosynthetic material will not degrade before several de-cades when used as a canal liner, or a geotextile filter inan agricultural function.

As the durability issue is often one of the concerns raisedby potential users, the industry has developed an array ofstrategies to assess the durability of geosynthetic materials,based on consensual methods. ASTM D 35, ISO TC 221and CEN TC 189 committees on geosynthetics offer dozensof standards solely focused on the evaluation of the durabil-ity of these materials, addressing most if not all the concernswhich may be faced given the particular material propertiesand service conditions considered. ASTM D5819–18 (2018)and ISO/TS 13434 (2008), for example, are intended toguide users in their quest to assess geosynthetic durability,whatever service condition or function is considered.

In the European Union, durability of geosynthetics is alsowell addressed thanks to a series of application standardswhich are the basis for granting a CE mark to candidateproducts. Among them, the characteristics required for theuse of a geosynthetic barrier (aka geomembrane) in the con-struction of reservoirs and dams (EN 13361, 2013), and ca-nals (EN 13362, 2013) are defined. In a similar fashion,other documents propose minimum characteristics requiredfor the use of a geotextile, or geotextile-related, product indrainage systems (EN 13252, 2016), erosion control works(EN 13253, 2014), reservoirs and dams (EN 13254, 2015)or canals (EN 13255, 2014). These technical requirementswere developed by Standardization Committee CEN TC189 considering a target durability of 25, 50 or 100 years,defined as a ‘conservative minimum’: as indicated in thesestandards, ‘the real working life may turn out to be consid-erably longer under normal conditions of use without majordegradation affecting the essential requirements’.

CONCLUSIONS

The use of geosynthetics has progressed significantlyover the past five decades. In the late 1990s, they were in-corporated into standards and legislation requirements foruse in critical applications, such as groundwater protectionand landfills. Their use as filters, stabilization and reinforce-ment materials was defined in transportation applications inthe 1990s as well. More recently, geosynthetics have beenidentified in the Water Resources Reform and DevelopmentAct (WRRDA) published in 2014 as one of the ‘durable, re-silient, and sustainable materials’ which should be consid-ered for developing and maintaining the (US) nation’swaterways and harbours, reducing damage from storm

events, and restoring the environment. This could not havehappened without a proven and well-structured approachto ensuring performance, thanks to the availability of numer-ous standards, engineering guidance and specifications, de-veloped by standardization bodies such as ASTM D 35,ISO TC 221 and CEN TC 189, among others.

The importance of cost-effective, environmentallyfriendly solutions is becoming a pressing requirement. Theuse of the geosynthetic products presented in this papercan satisfy containment, filtration and reinforcement func-tions required in irrigation, drainage and agriculture applica-tions, because while they protect and contain fresh water,they also impart a low carbon footprint solution comparedto concrete, bitumen, soil admixtures and compacted fine-grained soil.

REFERENCES

AASHTOM288. 2006. Geotextile Specification for Highway Applications -M288–06, Standard Specifications for Transportation Materials andMethods of Sampling and Testing. American Association of State Trans-portation and Highway Officials: Washington, DC, USA.

ASTM D4873/D4873M-17. 2017. Standard Guide for Identification,Storage, and Handling of Geosynthetic Rolls and Samples. ASTM Inter-national: West Conshohocken, PA, USA.

ASTM D5101 - 12. 2017. Standard Test Method for Measuring the Filtra-tion Compatibility of Soil-Geotextile Systems. ASTM International, WestConshohocken, PA, USA.

ASTM D5514. 2018. Standard Test Method for Large-Scale HydrostaticPuncture Testing of Geosynthetics. ASTM International: WestConshohocken, PA, USA.

ASTM D5819–18. 2018. Standard Guide for Selecting Test Methods forExperimental Evaluation of Geosynthetic Durability. ASTM Interna-tional: West Conshohocken, PA, USA.

EN 13252. 2016. Geotextiles and geotextile-related products - Characteris-tics required for use in drainage systems. CEN, European Committee forStandardization: Brussels, Belgium.

EN 13253. 2014. Geotextiles and geotextile-related products. Characteris-tics required for use in erosion control works (coastal protection, bankrevetments). CEN, European Committee for Standardization: Brussels,Belgium.

EN 13254. 2015. Geotextiles and geotextile-related products - Characteris-tics required for use in the construction of reservoirs and dams. CEN,European Committee for Standardization: Brussels, Belgium.

EN 13255. 2014. Geotextiles and geotextile-related products - Characteris-tics required for use in the construction of canals. CEN, European Com-mittee for Standardization: Brussels, Belgium.

EN 13361. 2013. Geosynthetic barriers - Characteristics required for usein the construction of reservoirs and dams. CEN, European Committeefor Standardization: Brussels, Belgium.

EN 13362. 2013. Geosynthetic barriers - Characteristics required for usein the construction of canals. CEN, European Committee for Standardi-zation: Brussels, Belgium.

GRI GM13. 2016. Test Methods, Test Properties and Testing Frequencyfor High Density Polyethylene (HDPE) Smooth and TexturedGeomembranes for geomembranes. Geosynthetic Institute: Folsom,PA, USA.

ISO 10318–1. 2015. Geosynthetics - Part 1: Terms and definitions. ISO, In-ternational Standards Organization: Geneva, Switzerland.

16 E. BLOND ET AL.


ISO/TS 13434. 2008. Geosynthetics - Guidelines for the assessment of du-rability. ISO, International Standards Organization: Geneva, Switzerland.

Morrison WR, Comer AI. 1995. Use of Geomembranes in Bureau ofReclamation Canals, Reservoirs, and Dam Rehabilitation. Rec-95-01,Bureau of Reclamation, December.

Stark TD. 2017. Pond Leakage Calculator - May, 2017. Excel spreadsheetsoftware. Fabricated Geomembrane Institute at University of Illinois atUrbana-Champaign, USA.

Stark TD, Hynes JM. 2009. Geomembranes for Canal Lining. Proc.Geosynthetics 2009 Conference. Salt Lake City, Utah, USA.

Stark TD, Slifer S, Monley G. 2005. Saving Prospect Lake Using PVCGeomembranes. Geotechnical Fabrics Report, Industrial Fabrics Associ-ation International, 23(9), December, 28–33.

Swihart JJ, Haynes JA. 2002. Deschutes - Canal-Lining DemonstrationProject, Year 10 Final Report. R-02-03, Bureau of Reclamation,November.



Documents

Applications of Geosynthetics to Irrigation, Drainage and