The quality of this digital copy is an accurate reproduction of the original print copy THE UNIVERSITY OF NEW SOUTH WALES MONITORING OF BED LOAD DISCHARGE IN N.S.W. RIVERS

ANTHONY JAMES McCABE

MASTER OF ENGINEERING SCIENCE DEGREE 1989 1. STUDENT'S DECLARATION

a. This is to certify that I , A^JHP.'i^y , being a candidate for the degree of Master of Engineering Science am fully aware of the policy of the University relating to the retention and use of higher degree projects, namely that the University retains the copies of any thesis submitted for examination, "and is free to allow the thesis to be consulted or borrowed. Subject to the provision of the Copyright Act (1968) the University may issue the thesis in whole or in part, in photostat or microfilm or other copying medium". I also authorize the publication by the University Microfilms of a 600 word abstract in Dissertation Abstracts Intemational (D. A. I.).

b. I hereby declare that none of the work in this project has been submitted to any other institution for the award of a higher degree.

Signature : '

2. SUPERVISOR'S CERTIFICATION

I cenify that this project has been completed under my supervision and is in my opinion in a fonn suitable for examination as part of the requirement for admission to the degree of Master of Engineering Science.

Signature : s) Project Supervisor c^ ^ ^ Q 11

ABSTRACT

The lack of reliability under field conditions of existing empirical methods for predicting the transport rate of bed load material in NSW rivers has led the Department of Water Resources to implement a technique which allows direct measurement. The aim is to prevent channel degradation caused by the uncontrolled removal of sand and gravel by the extraction industry for use by the building industry.

The method employs a post flood event chain/tracer technique to allow estimation of the volume of material moved during a flood. Combination with streamflow records allows calculation of the rate of movement. This report is based on the Author's involvement in the development and implementation of the program for monitoring bed load discharge. It describes the basis of the monitoring technique and discusses practical aspects of the implementation of the monitoring program. The amount of data available to date is limited, but some tentative conclusions concerning the relationship between bed load discharge and streamflow parameters are examined. Ill

ACKNQWT.BDGEMEMTS

The completion of this project would not have been possible without the assistance and guidance of DWR staff in the Catchment Management Unit.

Thanks to Mr. Michael Eather, Engineering Assistant, for his invaluable field knowledge of each of the monitoring sites and of the procedures used in the data collection. To Mr. Bruce Coates, Scientific Officer, for his guidance on theoretical aspects of bed load movement and general stream morphology, and thanks to Ms Marie Byers for the typing of the text. IV

TABLE OF CQNTENTS PAGE Student's Declaration and Supervisor's Certification i

Abstract 11 Acknowledgements iii List of Figures vii List of Tables viii

1. INTRODUCTION 1 1.1 The Problem 1 1.2 The DWR's Approach 2 1.3 Location of the Monitoring Sites 3 1.4 Sites to be Examined 3 2. POST EVENT CHAIN/TRACER METHOD 6 2.1 Introduction 6 2 - 2 Theory 6 2.3 Setting Up A Monitoring Site 8 2.3.1 Survey of Site 8 2.3.2 Selection of Tracers 9 2.3.3 Tracer Preparation 12 2.3.4 Scour Chain Placement 13 2.3.5 Placement of Tracers 19 2.3.6 Monitoring of Sites Between Events 19 2.4 Resetting a Site 20 2.4.1 Location of Scour Chains 20 2.4.2 Tracer Location 22 2.4.3 Resetting Scour Chains 23 2.4.4 Placement of New Tracers 23 TABLE QF CQMTENTS (Cont.) PAGE 2.5 Analysis of Field Dat:a 24 2.5.1 Reduction of Basic Field Data 24 2.5.2 Tracer Location Data 24 2.5.3 Scour Chain Data 25 2.5.4 Bed Load Volume 26 2.5.5 Bed Load Discharge 27 WILSON RIVER 29 3.1 Site Location 29 3.2 Site History 29 3.3 Detailed Results 34 NEVER NEVER RIVER 42 4.1 Site Location 42 4.2 Site History 42 4.3 Detailed Results 49 4.3.1 Field Trip 1 - May 1988 49 4.3.2 Field Trip 2 - December 1988 54 4.3.3 Field Trip 3 - May 1989 55 4.3.4 Summary 60 5. NUMERALLA RIVER 61 5.1 Site Location 61 5.2 Site History 61 5.3 Detailed Results 68 5.3.1 Field Trip 1 - September 1988 68 5.3.2 Field Trip 2 - July 1989 70 VI

TABLE OF CONTENTS (nonl:. ^ PAGE 6. CONCLUSIONS 73 6-1 General 73 6.2 Recommenda-tions for Future Development 73 6.3 Further Analysis 77 REFERENCES 79 APPENDICES Appendix A Field Sheets 80 Appendix B Programs 85 Vll

LIST OF FTCnWES PAGE

1.1 Location of Monitoring Sites 4

2.1 Idealised Illustration of the Transported 7 Volume of Bed Material

2.2 Wilson River - Particle Size Distribution 11

2.3 Principal Axes of a Rock Particle 12

2.4 Illustration of Scour Chains in Different 14 Conditions During A Flood Event

2.5 Chain Placement by Excavator Method - 16 Wilson River Site

2.6 Chain Placement by Star Picket Method - 17 Wilson River Site

2.7 Steel Plate Used in Star Picket Method 18

2.8 Scour Chain Elbow Illustrating Scour 21 and Fill

3.1 Wilson River Locality Plan 30

3.2 Wilson River Base Plan 31

3.3 Wilson River Monitoring Site 33

3.4 Wilson River - Location of Series 1 35 Tracers - June 1988

3.5 Wilson River - Transect Movement 37 - Trip 1

3.6 Particle Size v Distance Moved - Wilson 40 River - Series 1 - Trip 1

4.1 Never Never River Locality Plan 43

4.2 Never Never River Base Plan 44

4.3 Never Never River Monitoring Site 46

4.4 Never Never River - Transect Movement 52 - Trip 1

4.5 Duration Above A Base Flow Rate 59 - Floods in Never Never River

5.1 Numeralla River Locality Plan 62

5.2 Numeralla River Base Plan 63

5.3 Numeralla River Monitoring Site 65 vili

LIST OF TART.ES PAQE

1.1 Monitoring Site Details 5

3.1 Wilson River - Series 1 Tracers 36 - Located June 1988

3.2 Wilson River - Scour and Fill - June 1988 38

3.3 Duratio- Apriln 198 and8 VolumFloode -Abov Wilsoe an Bas Rivee rFlo w Rate 41 4.1 Never Never River - Series 1 Tracers 51 - Located May 1988

4.2 Never Never River - Scour and Fill 51 - May 1988

4.3 Duration Above a Base Flow Rate - April 53 1988 Flood - Never Never River

4.4 Never Never River - Series 1 Tracers 54 - Located December 1988

4.5 Never Never River - Series 2 Tracers 55 - Located December 1988

4.6 Never Never River - Series 1 Tracers 56 - Located May 1989

4.7 Never Never River - Series 2 Tracers 57 - Located May 1989

4.8 Never Never River - Series 3 Tracers 58 - Located May 1989

4.9 Flood Details for Never Never River 56 Between Trips 2 and 3

4.10 Duration and Volume Above Threshold of 60 Motion for Floods in Never Never River - Trips 2 to 3

5.1 Flood Details for Numeralla River Site 68

5.2 Numeralla River - Series 1 Tracers - 69 Located September 1988

5.3 Duration Above A Base Flow Rate - 69 Numeralla River Floods From Set-up to Trip 1

5.4 Duration and Volume Above Threshold of 70 Motion - Numeralla River - Trip 1

5.5 Numeralla River - Series 1 Tracers 71 - Located July 1989 IX

LIST OF TABI^ES icont:. > PAGE

5-6 Numeralla River - Series 2 Tracers 72 - Located July 1989

A.l Tracer Measurement Sheet 81

A-2 Tracer Location Sheet 82

A.3 Scour Chain Details Sheet 83

A.4 Tracer Recovery Sheet 84

B.l ROCKID Program Listing 87

B.2 REDUCTN Program - Sample Input and Output 89

B.3 Listing of XSECT Program 91

B.4 Sample Output from XSECT Program 92

B.5 Data Entry Requirements for TRANS Program 92

B.6 TRANS Program Listing 93

B.7 Listing of RATE Program 98 # I INTRODUCTTQN

The ProblQin The extractive industries of this State depend heavily on it's rivers for the supply of sand and gravel for subsequent use in the construction industry.

Problems occur however, if the rate of removal by the extractors equals or exceeds the long term natural replenishment rate. River degradation can result, and this in turn can cause river bank instability and lead to a decline in water quality.

The Department of Water Resources (DWR) is the State Authority responsible for the formulation of policies and environmental options for gravel extraction in all non- tidal sections of the rivers in NSW. Appropriate legislation is under the Rivers and Foreshores Improvement Act (1948).

The DWR has recognised that its policies are currently inadequate and this, in combination with the extractive industries insatiable demand for gravel, has lead to river degradation problems throughout NSW. For example, in the Cockburn River near Tamworth, channel degradation of up to 2 metres has been experienced over the last ten years. During this period, some 160 000 tonnes per year of gravel has been extracted from the river without control.

Problems such as these could be avoided if the natural rate of replenishment could be scientifically determined before an extractor was allowed to remove any material from a site.

By identifying such information, an extraction management plan could then be formulated for all river reaches in the State where there is or will be, a demand for sand and gravel. In this way the stability of the riverine environment in the long term can be assured along with satisfying the demand for riverine material by the building industry.

Determining this rate of replenishment or more specifically the bed load discharge, is however not straightforward. Several attempts at predicting the transport rate at sites throughout NSW have been made using an empirical approach. This approach has not been successful. Equations developed overseas appear to be innately unreliable under field conditions in NSW rivers as their predicted rates vary over several magnitudes depending on which equation is used (Hean & Nanson 1987).

Accordingly, the bed load discharge must be determined by direct measurement methods to prevent channel degradation, and to avoid placing unnecessary restrictions on the extractive industry. The DWR^s Approach Numerous methods of bed load measurement have been tried both in Australia and overseas. For example, direct methods such as the use of pits or slots, site surveys, bed load sampling and post event tracer measurements have been developed. All methods of course have inherent advantages, limitations and inadequacies. For example, the use of a bed load sampler during a flood event provides direct measurement of the rate moved. However, such samplers can only be used on small streams with shallow activation areas. They are impractical for use on medium or large rivers with infrequent movement of sediment and require measurement at the time, and throughout, a flood. Accordingly, the methods of measuring bed load movement after the event are more practical, and a technique which combines survey and a post event scour chain/magnetic tracer method as suggested by Hassan et al (1984) has been adopted by the Department. Briefly, a site selected for monitoring is initially surveyed to establish the general morphology of the river channel. Scour chains, which remain vertical unless scour occurs, are installed across the river channel to measure the area of activation. This cross section is referred to as the transect. Magnetic tracers are then placed on the transect as a line source. These are painted, numbered rocks which have an inserted magnet and which have a size distribution similar to that of the natural bed material. They are used to provide a measurement of the distance the bed material is moved during a flood event. Following a flood event, the site is resurveyed to identify changes in the channel morphology, and the scour chains are measured to determine the amount of scour and fill which has occurred. The magnetic tracers are recovered by use of magnetic detectors and their new positions surveyed. The scour chains are then reset vertically and a new series of tracers placed for the next event. A detailed account of the establishment of a site and its continued monitoring is given in Sections 2.3 and 2.4. By combining the scour chain information and the tracer movement information collected, the volume of sediment moved in a flood event can be calculated. With the establishment of the threshold of motion from the streamflow records, the bed load discharge can then be calculated. : , ^ / 3

Details of the analysis of the collec&e€i-^;3da;fca: is given in Section 2.5. As the above technique had never been used by the DWR^ a consultant Dr. J.B. Laronne was commissioned to commence the program and select appropriate monitoring sites on rivers identified by the Department. The program was initially scheduled for a period of five years. However as both hydrologie and sediment supply rates are variable, depending on temporal and spatial changes, it is now intended that this program will be a permanent, ongoing project to provide a mechanism for the monitoring of any long term change in a river system. As the program was only initiated in late 1987, insufficient data has been collected to date to allow any firm conclusions to be drawn for any particular monitoring site. Therefore, this report describes the progress of the monitoring, and the tentative conclusions drawn to date. It suggests several improvements to the techniques used in data recovery and illustrates the procedures for analysis of the data. Location of the Monitoring Sites The overall program set-up by the Department involves the monitoring of eight sites, and includes all priority one sites identified by Dr. J.B. Laronne in his report to the Department. The locations of these sites are shown in Figure 1.1. The sites were chosen from rivers where bed degradation is occurring or where this is likely to occur due to the removal of bed load material (namely sand and gravel) by the extractive industries. The actual location of the sites in the river system must be carefully selected to avoid the occurrence of unstable reaches where short term aggradation or degradation is developing. The Wilson River site discussion expands this concept further. Table 1.1 shows the location of the monitoring sites and pertinent data on .their establishment and monitoring exercises. 1,4 Sites To Be Examined For this project, an examination will be made of the following sites:- Never ¿Never River Numeralla River Wilson River QUEENSLAND

NEVER NEVER RIVER COFFS HARBOUR BELLINGER RIVER COCKBURN RIVER

WILSON RIVER

PORT MACQUARIE

PAGES RIVER

A , CANBERRA^—MURRUMBIDGEE RIVER

NUMERALLA RIVER

Figure 1.1 Location of Monitoring Sites

These sites have been chosen for 1) the variety of location throughout NSW; 2) the availability of streamflow records up to mid 1989; and 3) availability of bed load volume data. For comparison purposes, the three monitoring sites represent a good range in hydrologie conditions and geomorphology throughout the State. The Wilson River is a tributary of the Hastings River. Physiographic features of the River include rugged slopes generally above 15 degrees in the head-waters with large areas heavily forested on soils derived from granites or sedimentary rocks. Average annual rainfall over the catchment is 1270 mm. This usually falls as very heavy rainfall from depressions located off the northern coast of NSW. The Never Never River is part of the Bellinger River Valley and rises in the extremely rugged fringe of the Dorrigo Plateau which has a general elevation above 900 metres. The catchment is characterised by rugged heavily timbered country. The average annual rainfall is a high 1650 ram which generally occurs in Summer. The geology of the catchment consists of metamorphic rocks belonging to the Silurian Period. River Site Date Gauging Number Established Station of Resets

Bellinger D/S Wills Feb 1988 205002 2 Bridge

Cockburn U/S Mulla Nov 1987 419016 1 Crossing

Murrumbidgee Bredbo Feb 1988 410050 1

Never Never D/S Feb 1988 205014 3 Glenniffer Bridge

Numeralla Numeralla Feb 1988 410062 2

Wilson LamefieId Dec 1987 207014 1

Pages Allan's Mar 1988 210052 2 Bridge

Hunter Denman Dec 1988 210055 1

Table 1.1 Monitoring Site Details

As a head-water tributary of the Murrumbidgee River, the Numeralla River is characterised by the rugged slopes of the Monaro Range. The catchment's geology is primarily granite rocks in the head-waters and slate, sandstone and limestone from the Ordovician Period in the lower sections. Average annual rainfall is a low 500 mm with 60 per cent of the rain received in the period from October to March. Severe frosts and snow occurs in places over 900 metres.

Critical to the study is the need for good quality streamflow data. The three sites chosen for analysis have this streamflow data available up to the last field, undertaken, from the gauging stations listed in Table 1.1. V The location^ of these stations in comparison to the monitoring sites is discussed in the site location sections in each relevant chapter.

The sites have also been reset at least once and in the case of the Never Never River site, a total of three times. POST EVENT CHAIN/TRACER METHOD

2-1 Introduction As mentioned earlier, the DWR has adopted a technique which combines survey and a post event scour chain/magnetic tracer method for measuring bed load movement in several rivers throughout NSW.

This method was suggested by Hassan et al (1984) in their study of an emphemeral channel bed in Israel. The study involved the determination of cross sectional changes in the river by use of scour chains and monitoring the dispersion of labelled particles based on magnetic tracing. The following section briefly provides the theory of this type of post event method, as stated by Laronne is his report to the Department on his consultancy to establish the bed load monitoring program.

The actual sites included in the DWR's program were recommended by Dr. Laronne, on rivers identified by the Department as being in danger or soon to be in danger from bed degradation due to the extraction of gravel.

Section 2.3 provides a step-by-step description of the procedure for establishing a monitoring site, whilst the procedures necessary for collecting the data after a flood event are given in Section 2.4. Lastly, a guide to the analysis of the field data is described in Section 2.5.

Theoiy During a flood event, the volume of bed material transported may be determined from estimates of the dimensions of the transported bed layer and the associated distance moved. An idealised illustration is shown in Figure 2.1.

In moderately large flood events, it has been found that in eastern NSW rivers, the entire river bed width becomes activated. This may of course vary among events, and may in fact only comprise selected areas of the river bed.

The distance of bed load material moved, L, will also vary between events depending on the magnitude of the flow causing the movement and in particular, the length of time above the threshold of motion for the bed material.

The depth of activation may have a positive value (fill), as well as negative (scour). As suggested by Laronne (1987), if the depth of activation is determined solely by scour, the volume of bed material moved can be calculated from: = S W^ L (1-n) (2.1) where = volume of bed material (m^) ) = average scour depth (m) W. = width of activation (m) = average distance of transport (m) and n = porosity of the bed material

Depth oi Activation

Figure 2.1 Idealised Illustration of the Transported Volume of Bed Material- If only fill occurred, for the subject reach would be zero, however the average fill depth could be substituted into Equation 2.1 to determine the bed load volume moved from the reach where the deposit originated. If however, both scour and fill occur during a single event, then Vj^ can be calculated as follows: Vt = W- L (1-n) ( |S|+F)/2 (2.2) From Equation 2.2, it can be seen that the method employed must be capable of measuring 1) the average distance moved and 2) the change in cross section during a flood event. Particle tracing indicates the distance of travel during a flood event. This requires the placement of magnetically tagged particles across the active bed load zone (transect). After a transport event, the particles are relocated and the distance from the original point is measured. Channel changes can be identified by survey and the use of scour chains, which allow measurement of scour and fill separately during a flood event. The principle of a scour chain is that it remains vertical within the bed unless the bed is scoured.

The following sections discuss more fully the principles involved in both these measurements.

The above method gives a volume of bed load material moved. However this infoinnation is of no use unless the rate of movement can be determined, thereby producing a discharge. The rate of movement depends on the duration of flow above the threshold of motion for the natural material. Therefore, the volume measurements must be combined with the corresponding streamflow measurements for a flood event.

This will result in a bed load discharge v flow volume curve, which can then be used to yield an average annual bed load discharge for the long term regime of flow, provided that hydrologie response and sediment supply rates remain consistent.

—Setting UP A Monitoring Site The selection of the actual sites in the Department's monitoring program resulted from many factors. Priority however, was given to those rivers in danger or soon to be in danger from bed degradation due to extraction of gravel.

The following is a step-by-step description of the procedures for setting up a site.

2-3-1 Survey of Site To enable the changes in cross sectional area at the site to be monitored and for tracer location after each flood event, a detailed stadia survey needs to be undertaken on establishment of the site.

This requires the set-up of bench marks along the reach of the river under study so that all data gathered in future trips will be related to a common datum and reference point.

As the sites are generally on remote rural properties, the bench marks are not tied into any known datum such as Australian Height Datum. Therefore all levels at a site are to an assumed datum.

In general, the bench marks for each site are steel bolts placed in concrete pads at an interval of about every 200 metres. They should be set back from the top of the river bank to maintain their permanence after future flood events. The first bench mark should be placed at the transect and given arbitrary co-ordinates of 1000 metres east, 1000 metres north and a reduced level of 100.00 metres assumed datum. The location and height of each further bench mark downstream can then be related to this first bench mark. From these marks, detailed stadia and cross sectional information can then be taken. In general, for preparation of the base plan, the top of bank, bottom of bank and low flow channel should be located for the reach under study together with any distinguishing features such as gravel bar location, living or fallen trees etc. A cross section of the river channel should be taken along the line of the transect plus at any location downstream where major changes in grade or channel configuration occurs so that after future flood events, changes to the channel morphology can be quantitatively identified. From this information a base plan of each site can be drawn. An example for the Never Never River site is shown in Figure 4.2. 2.3-2 Selection of Tracers An important aspect of the monitoring of bed load movement is the selection of the rocks to be used as tracers. The distribution and size of these tracers should be representative of the natural material in the zone of anticipated scour at a particular site to ensure accurate modelling of the movement of the bed material. To determine the natural composition of the bed material, several techniques can be used. One involves taking a bulk sample whereby a predetermined volume of material is taken from an exposed bar, generally with a shovel. An alternative method is a grid sampling procedure of the surface material. A 10 x 10 metre grid is laid over a gravel surface and the particles immediately beneath the grid points constitute the sample. Once the sample has been collected, by whatever method, a linear dimension of grain size has to be assigned to each particle. The intermediate or b-axis is generally accepted as the definition of grain size by most investigators. The sample is then divided up into size classes and the frequency by either weight or number is recorded. As with any sampling method, the degree to which the sample represents the population is dependent on a number of factors. Lateral variations within a reach of river can be rather abrupt for no apparent hydraulic reasons. Time variations can occur in some river beds depending on season or elapsed time since the last major flood event (Kellerhals & Bray 1971). 10

With these factors in mind, the choice of the sampling site should be carefully chosen, and it is recommended that several locations should be sampled so that an accurate distribution can be obtained. Also, future samples should be undertaken after every two or three flood events to ensure the distribution is maintained or so that tracer distribution can be suitably adjusted.

For example, both techniques were used in the Wilson River site set-up with results as shown in Figure 2.2. From this size distribution, the tracers were selected so that their distribution fell into the same range as the surface sample taken using the grid method. Note, the parameter 0 is the negative logarithm to base 2 of the grain size of a particle in millimetres.

The above discussion gives the procedure used in determining the size distribution for the tracers. The next step is the supply of suitable rocks for use as tracers.

Initially for the Never Never River site, rocks from an exposed bar near the site were selected according to a similarly worked out size distribution and taken back to Sydney for preparation. This was satisfactory for this particular site but for other sites it was found that the rocks were unsuitable, as the majority shattered upon drilling.

With these physical constraints, and the cost constraints in travelling to a remote site every time a sample was required, alternative sources for the rocks were investigated.

Rocks from an exposed gravel bar in the Hawkesbury River were tested for drilling due to their proximity to testing facilities. However the hardness of the rocks caused drilling problems and this source was therefore rejected.

A further supply of rocks from the Minnamurra River just upstream of Jamberoo on the South Coast was tested and found to be acceptable for drilling and in terms of compatibility with the shape and density of the rocks at each site.

Therefore, tracers are now selected according to the size distribution for the desired site from the Minnamurra River. They are selected at random but keeping in mind their suitability for drilling. Typically 10 to 20 per cent of the rocks will shatter upon drilling. Therefore, if a sample size of 150 tracers is required, a total of say 200 rocks will be collected from the source site. FIGURE 2.2

WILSON RIVER - PARTICLE SIZE DISTRIBUTION

20- BULK VOLUME SAMPLE

15.

10,

5.

0

GRID TECHNIQUE SAMPLE 25

20

15 CO cc LU OQ 10

5 >- >CD O 0 2 HI •D o ill DC SERIES ONE TRACERS U- 50,

40.

30.

20.

10

I I 1 —' —I I— -7.5 -7 -6.5 -6 --5.5 -5 -4.5 -4 -3.5 -3 -2.5 0 12

2.3.3—Tracer Preparation After selection of the rocks, the following procedure is undertaken to prepare the tracers for use at a monitoring site. Using a drill press operating at about 100 rpm and a drilling rate of 100 irmi/min, a hole is drilled in each rock. The size depends on the subject rock but typically has dimensions of 15 mm diameter and a depth of 6 to 12 mm. The rocks are then washed of the oily lubricant used whilst drilling then dried in preparation for insertion of a ceramic magnet. The magnets used are anisotropic ceramic magnets with diameters of 12 mm and depths of 6 mm. They are placed in the drilled hole in the rock then sealed with an epoxy cement. As suggested by Laronne (1987), the entire operation brings about a weight loss of less than 0.5 per cent. Each particle is then painted to enable easy detection after placement. It has been found that a rubber based monopreen paint is resilient to the abrasive forces in the movement of the tracers in a flood event. Upon drying, the tracers are then numbered using a contrasting colour and the principal axes of the particle (as shown in Figure 2.3 ) are measured and recorded . An example field sheet is also given in Table A.l.

PLAN VIEW END ELEVATION

Figure 2.3 Principal axes of a rock particle 13

Laronne suggested drawing a scatter diagram showing the variation of grain size (b-axis) with both elongation (a-axis) and thickness (c-axis). This would allow identification of particles whose numbers were erased after transportation during a flood event.

Lastly, it may also be useful to weigh each particle for analysis of the movement of each individual particle, although this was not done in the cases discussed in this report. 2-3-4 Scour Chain Placement

Scour chains are necessary in the monitoring of a site to separately measure the scour and fill which occurs during a flood event. The principle in the use of scour chains is that they remain vertical unless scouring of the bed occurs.

Figure 2.4 (Laronne 1987) illustrates scour chains in several scenarios during a flood event.

The number of scour chains to be used depends on the width of the river channel at the site. A chain spacing of between 2 and 4 metres has been found to adeguately measure the bed movement during a flood event.

The chains used in the Department's program are galvanised iron (5 mm thick) with a 25 mm link length. As sugg^ted by Laronne (1987) these chains will remain stable(jorr^the bed unless general scour occurs, and will not induce~"local scour because the link length is eguivalent to or smaller than the average gravel bed roughness.

The length of chain used is site specific depending on the depth of gravel deposition. A length of 1.0 to 1.5 metres has commonly been used.

Placement of the chains has undergone considerable development since the start of the program. As recommended by Laronne (1987), a hydraulic excavator was first used to place the scour chains. The chains were attached by a gang nail to a wooden board about 300 x 400 x 50 mm in dimension to provide an anchor to resist movement.

Figure 2.5 shows this type of placement at the Wilson River site. The method is very labour intensive and care must be taken to ensure the chain is placed vertically when backfilled. A further problem is that of compaction as the local area is now a very disturbed sample and may not adequately represent the natural compaction of the gravel bar. Another major disadvantage of the method is the high cost of using an excavator in such remote areas.

Note also, that at the Wilson River site, the method did not prove greatly successful as after the first flood 14

event, 8 out of 30 chains placed were lost. In fact, one of the chains was found downstream attached to only a small portion of the wooden board, suggesting that these anchors were unsuitable to withstand the high velocities during a flood event.

® l-D. . 0 - ^ 1 0 - 8

• ¿•^•J « « 0 ^ Q o ^ DX

• 0 OA • < ^ (3 •. . • ^ A o •.••j >.0

. o »

fc o • . ^^ • • o ^^ • ^ <"3 * o I.D.- • o 0 o ' C> '

o O' O o o • « 0' • '• O . o. o . . . o .0 o .".0 "'•om.^ • ''bM-' , o

II . . . Ill e o o• • • o » I.D. T o • o ^iCBO O . S. ' O .1' • O O' 'o>fl •ci-' O O <—«' ® A • O O • '51 • • O Ao . o . Q A • * A o . 0 T c>. . C>

o • • .. -.A5 •« • 0 • • • '_X_8 '' • 0^ ••am'. . O Figure 2.4 Illustration of scour chains in different conditions during a flood event. Note, I.D. indicates initial datum. 15

Another method experimented with for placement of the chains involved insertion by a water jet technique. This involved forcing the chain vertically into the bed by water pressure generated by a petrol driven pump. This method was tried unsuccessfully at the Never Never River site. It was found that insufficient power could be generated to drive the chains into beds with coarse gravel, especially on the gravel bars away from the river channel, which is the source of water for the pump. No anchors could be attached to the chains, so the method is also unsuitable for sandy sites. The preferred method of placement, as shown in Figure 2.6, is known as the star picket method. Briefly, this method involves driving a length of chain attached to a common star picket into the bed, then removing the picket by leverage, leaving the chain in place with a minimum of disturbance to the bed. In more detail, the chain is attached to a star picket by a wire at the top and hooked on a nick cut near the bottom of the picket. The picket and attached chain are then placed through a steel plate into which a star picket shaped slit has been cut (shown in Figure 2.7). This plate is used for gripping the picket on removal. Through a guide in the end of the plate, a crow bar is inserted and laid on the ground perpendicular to the star picket. Driving into the bed is achieved by use of a hand held pile driver and completed by use of a sledge hammer. Care is necessary in the initial stage to ensure the chain is still held by the nick in the bottom of the picket. Removal of the star picket after cutting of the tie wire involves levering with the crow bar. The steel plate grabs the picket allowing gentle removal. The chain is left in place with a minimum of disturbance to the bed. This method is cheaper than the previous methods discussed and has not lead to any decrease in the rate of recovery in gravelly sites. However problems in sandy sites have been identified. Several improvements and different methods have therefore been mooted to increase the permanence of each site's scour chains. For the star picket method, the addition of a piece of steel at the end to act as an anchor has been suggested. This would involve connecting the end of a chain to a length of star picket (say 20 cm long) which is then driven vertically using the same method as described above. During a flood event, any movement of the chain will cause FIGURE 2.5

CHAIN PLACEMENT BY EXCAVATOR METHOD

WILSON RIVER MONITORING SITE FIGURE 2.6

CHAIN PLACEMENT BY STAR PICKET METHOD

WILSON RIVER MONITORING SITE 18

the anchor to wedge against the rocks in the bed, thereby increasing its resistance to movement. A more permanent method which would be applicable to sandy sites would be to physically attach the end of the chains to the bed rock. From experience it has been found that bed rock in active zones is located close to the surface. For example at the Cockburn River site near Tamworth, the bed rock in the low flow channel is only about 0.5 metres below the surface. The bed rock could therefore be exposed by excavation, and a bolt placed into the rock. A length of chain could then be attached and the hole backfilled. Compaction problems will result in the short term, but after one or two flood events, a more natural compaction should be returned. Alternatively, a concrete pad could be placed on the bed rock if the location could be made waterproof enough for the placement of a sand and cement mortar.

STAR PICKET INSERTED

t CROW BAR INSERTED

y STEEL PLATE

PLAN VIEW

Figure 2-7 Steel Plate used in Star Picket Method It is expected that the two methods described above would OAly be used at those sites where problems are experienced and only in those sections of the channel exposed to high velocities during flood events. Substantial effort in ensuring the continued permanence of the scour chains is justified, as the information yielded 19 by the chains is vital to the whole data collection program and subsequent analysis of this data.

Finally, after placement of the scour chains at a particular site, the length of chain left exposed due to variations in gravel deposition or the proximity of the bed rock is recorded on a field sheet. An example is given in Table A.3.

2-3-5 Placement of Tracers With the survey of the river reach and transect, the preparation of the tracers and placement of the scour chains, the site is now ready for the placement of the tracers so that monitoring can be commenced.

As suggested by Laronne (1987), in this monitoring program a line method of tracer placement has been adopted. This involves placing the tracers along a line across the river where the scour chains have been placed.

The number of tracers placed is dependent on the width of the river channel and gravel bar. Laronne (1987) suggests placement of one particle buried about 30 cm at each chain plus at least two other particles beside the chain on the surface. Additional particles should then be placed between each chain.

In practice, a total of 5 rocks were generally placed at each chain, one of which was buried about 15 cm below the surface. The number placed in between the chains is dependent on the distance separating them. For example, on the Never Never River site, a total of 14 chains were installed to cover the 40 metre channel width. Four to five tracers were placed between each chain across the transect, giving a total number of 150 tracers.

The method of placing the rocks is to randomly select a tracer from a bag so that a good representative distribution is placed over the entire transect. On placement of each rock its location is recorded on a field sheet similar to that presented in Table A.2.

Lastly, photographs of the site, particularly along the transect and upstream and downstream along the gravel bar should be taken so that visual comparisons after future flood events can be drawn.

2.3.6 Monitoring of Sites Between Events

With the placement of the tracers, the site is now ready for monitoring to commence, awaiting the occurrence of a flood event. It is desirable for some form of flood monitoring schedule to be available so that the occurrence of a flood can easily be detected. For example, use of telemetry if installed at the streamflow gauging station for the site; regularly monitoring daily river reports for a nearby station; or use of local office reports. 20

Of critical importance to the program is the identification of the threshold of motion for each particular site. A schedule of inspecting the site should be implemented so that the "start to move" flow for each site can be established. For example, at the Never Never River site, the re-setting of the site at Trip 1 could not be undertaken due to time constraints. The rocks from Series 1 had been relocated and the scour chains measured but the resetting was not done until one month later. In between, a small flood occurred causing slight movement of those tracers on the surface near the transect. The flow therefore would give a very good indication of the threshold of motion. Unfortunately the gauging station recorder malfunctioned at this time. It is therefore recommended that regular visits to the site be performed to check on movement until this "start to move" flow is established.

2,4 Resetting a Site This section gives a step-by-step description of the resetting of a monitoring site following a flood event. Sufficient time for the recession of the flood should be allowed so that all areas, including pools can be easily searched. 2-4,1 Location of Scour Chains Locating the transect after a flood event is not as easy as one first imagines. Numerous changes can occur at a site during a flood event and exact location can be difficult, even with the use of previous photos. However, the bench mark established on the transect is usually easily found and provides a good start in the location of the scour chains. It is useful to place a string across the channel to provide an upstream boundary for the area to be swept with the magnetic detectors. The detectors used by the Department are hiflux magnetic locators (Model GA- 52B) built by the Schonstedl Instrument Company. They are battery operated and have two cells that produce an electric current when placed close to a magnetic field. One cell is located at the bottom of the sweeping rod. The presence of a tracer (or any other metallic object) will create a difference in voltage between the two cells. This is then amplified by the detector to a loud, persistent, high pitch noise. Practical tests have shown the detectors can locate a tracer under water to at least 50 cm below the surface. 21

Using a sweeping motion, the scour chains across the transect are located. A shovel or hoe is then used to unearth any buried chains. On detection of several chains, the general line of the transect can be established. The survey of the transect when set-up can then be used, as the known distances between each chain can more accurately narrow down the areas to be searched. Once a chain has been located, the exact location of the chain elbow must be found to permit the actual amount of scour and/or fill to be determined. Figure 2.8 illustrates the scour chain elbow.

' CD '

Figure 2.8 Scour chain elbow illustrating scour and fill. From practical experience it has been found that the location of this elbow (E) is rather difficult, especially if the chains are located within or near the low flow channel. Care and persistence must be exercised. A note must be made of the distance from the end of the chain to the elbow (S), and then compared with the distance marked as original exposure to ensure the former is not less than the latter. All missing chains must also be duly recorded. Further, it has been found that measurement of the amount of fill (F) is difficult and subjective due to the disturbance of the local area when locating the chain. Surveying both the level of the elbow and the natural surface level when the chain has been reset is the preferred method. The difference in these levels will give the amount of fill. The difference between the reduced level of the elbow and the natural surface given for the pre-flood condition gives the amount of scour that has taken place in the flood event. 22

2.4,2 Tracer location After location of the scour chains, the next step involves the location of the tracers. Of course during the search for the chains, some of the tracers which did not move or moved only slightly are often located. The procedure described below for recording the number and location of each tracer was followed.

On finding a tracer, the location is marked with a numbered survey peg. On a field sheet, the colour and number of the rock, and the approximate depth below the surface is recorded, whilst the rock is marked off the tracer location sheet. The tracer is then returned to the place it was f.Qund and replaced. An example of such a field sheet is given in Table A.4.

In some instances, the rock number may have worn off. In this case, the principal axes of the rock are measured with a set of callipers and recorded in the field sheet for later identification.

From prac-tical experience it has been found that Vmeasurement" 6f the rock axes can be very subjective or • simply in error. Therefore, in the course of this project the method of identification has been improved by use of a computer program which uses the rock data base for > comparison with the subject rock. By simply summing the differences between the a, b and c axes of the subject rock with each rock in the data base respectively, the closest five alternatives are presented to the user. From this list (or more if required) the rock can then be identified. Appendix B1 provides a sample session for the identification of a rock in the Never Never River Series 1 data base.

To ensure that a thorough search across the channel and downstream along the entire reach under investigation is achieved, "lane ways" are marked with string. From the upstream boundary line, they are marked out about 2 metres wide. This width represents the limit of the normal sweep with the detector for an operator. In general, the lane ways are about 100 metres long, and once the area is searched, they are moved downstream and the sweep continued.

Particular attention should be given to shallow flow and bar areas and any other area that it is assumed likely to yield more tracers, for example, against a fallen tree or amongst an outcrop of vegetation.

Upon completion of the search, usually limited by time constraints and not upon finding all the tracers, the exact location of each tracer is determined by an electronic distance measurement system (EDM). In this program, the Department uses a Total Survey Station system which gives a bearing and distance from a known point to each tracer. 23

The procedure involves use of the established bench marks. The bearing from Bench Mark 1 to 2 (the baseline) is set at zero degrees, and Bench Mark 1 given the arbitrary co- ordinates of 1000 metres east, 1000 metres north. A set-up of the instrument at any point must be related back to this baseline so that all points can be determined relative to Bench Mark 1. Therefore for example if the instrument was set-up on Bench Mark 2, a shot would be taken onto Bench Mark 1 to establish the baseline and a bearing of 180 degrees would be set.

From this, all tracers are then surveyed and their position related back to the baseline. Upon survey of each tracer, the survey peg is marked off the field sheet and the tracer replaced as found. If it was buried, the hole is backfilled.

2-4.3 Resetting Scour Chains As mentioned earlier, on locating the scour chains several measurements are necessary to determine the actual scour and/or fill that has taken place.

Firstly, the reduced level of the elbow of each chain relocated must be surveyed. This is achieved by setting up the instrument on Bench Mark 1 and relating the levels of the elbow to the known bench mark level of RL 100.00 metres. The difference of this level and the natural surface of the point from the pre-flood transect gives the amount of scour which occurred during the flood event.

Following this, each chain is reset. This involves refilling the hole if fill has occurred whilst holding the chain vertically. Again, the length of chain left exposed was measured and noted on a field sheet.

If any chains are missing, new chains are installed (see Section 2.3.4 for details) and their exposure noted.

Lastly, a cross sectional survey of the transect is undertaken to give the shape of the transect after the previous flood event. The difference between this natural surface level and the level of the elbow gives the amount (if any) of fill that occurred.

2,4.4 Placement of New Tracers

After the site has been resurveyed, placement of new tracers is undertaken. This involves placing a different set of coloured tracers in accordance with the procedure listed in Section 2.3.5.

Note, after the site has been reset several times, a total of some 500 plus tracers may be in place. Depending on the recovery rate, this number should provide a meaningful average of distance moved. Therefore, the number of tracers can be reduced to say two at each chain and only one between the chains. This will allow a thorough search 24 of the entire reach and not just the first 100 metres due to the large number of particles being found.

Again, the placement of each rock is by random selection and the number is recorded on a field sheet.

Following photographs, the site is now ready for the next flood event.

Analysis of Field Data

One of the aims of this project is to establish a step-by- step guide to the analysis of the field data - scour/fill data, distance moved and streamflow data. The following sections detail the techniques used in the work carried out for this report and recommendations for analysis depending on the availability of the data.

2-5-1 Reduction of Basic Field Data All field data collected using the Department's Total Survey Station equipment is placed on the system's erasible memory modules, which are later downloaded to a personal computer for reduction.

The first step in analysis of the collected tracer location data and transect levels is to refer each point surveyed to a known reference point, namely Bench Mark 1.

The reduction of this basic data is achieved by use of a program written by Mr. Brian Franklin, called the REDUCTN program. This program takes the slope distance, deflection angle, bearing and rod height for each point and calculates its north and east co-ordinates and reduced level in relation to the instrument station. Tying in the instrument station to the baseline between Bench Mark 1 and 2 allows each point to be related back to Bench Mark 1. Further discussion of the use of this program is given in Appendix B2.

At this time, we must ensure the correct bearings have been set for each instrument set-up. If not, hand calculations and edits should be done to correct each point's bearing. 2.5.2 Tracer Location Data

Following use of the REDUCTN program, the tracer location data has a set of X-Y co-ordinates for each point. The data can then be plotted, typically as an overlay, on the appropriate base plan for the site.

Distance moved is calculated by simply measuring the movement of the tracer along a streamline. The streamlines are determined by the channel configuration.

A table of tracer numbers and distance moved (similar to Table 3.1 for the Wilson River) can then be drawn and average distance calculated according to the total transect 25 or into zones if the extent of bed activity dictates this. In such instances (as suggested by Laronne 1987) it is necessary to separately calculate the average distance moved for each zone.

2.5.3 Scour Chain Data As discussed in Section 2.4.1, when resetting a site the difference between the natural surface before the flood and the elbow of the scour chain gives the amount of scour that has occurred, whilst the difference between this elbow and the natural surface after the flood, the amount of fill. Therefore, from these measurements, the depth of activation during the flood is estimated.

Output from the REDUCTN program gives each point in the transect a set of co-ordinates and a reduced level related to Bench Mark 1. However for analysis of the transect, the distance between each point on the transect perpendicular to the direction of flow is required. Analysis then, requires calculating this cumulative distance with the origin, as convention dictates, commencing at the left bank.

A computer program called XSECT was written by the author to extract cross sectional details of chaînage and reduced level from the co-ordinate system used. A program listing, the input data required and a sample session is given in Appendix B3.

A further program, called TRANS was also written by the author to plot the cross sections. This allows graphical comparison of the transect during the different stages. Again the listing is provided in Appendix B4 togei^er with the input data requirements and a samplev^s^ssionV^ Figure 3.5 is an example of the output produced for the Wilson River.

Both programs were written in BASIC and compiled using the Microsoft QUICKBASIC Compiler V2.00. The TRANS program uses a ROLAND 980 X-Y Plotter.

The net area of activation can now be calculated. Two methods are available. Each will be discussed below, however from experience it has been found that the method of comparing cross sectional area under a stage height is by far the most efficient and quickest method, and has been used in all examples for this report.

The first method involves hand calculations from the chain measurements as suggested by Laronne (1987). This method requires comparison of the original length of exposure with the length of chain from the elbow to the end, and a hand measurement of the depth below the surface of the elbow. Scour is represented by the difference between original exposure and the elbow, whilst fill is the difference between the elbow and the natural surface. Addition of the absolute values and averaging of these measurements over 26 the transect gives the depth of activation. The width of activation is given by the width of channel moved during the event, from which the product with depth gives the net area of activation. The disadvantages of this method have been discussed previously in Sections 2.4.1 and 2.4.3 and as such is not recommended. The second method involves calculations on the difference in reduced levels of the before, during and after cross sections. For each segment, the average difference in level is multiplied by the distance separating each point and summed to give an overall area of activation. This method is recommended, by use of a computer program written by the author, called RATE. The RATE program requires entry of the cross section data to calculate the geometric properties of the section below a user-defined stage height. By comparison of the cross sectional area in the before, during and after stages, the sum of the absolute differences gives the net area of activation. A listing of the RATE program is given in Appendix B5 together with a sample session for illustration of the procedure.

2-5.4 Bed Load Vo1mnf> Calculation of the bed load volume moved between each reset is achieved according to Equation 2.2: Vj3 = Wa L (1-n) ( |S|+F)/2 From the recommended method in Section 2.5.3 using the RATE program, the net area of activation is calculated. This is actually the product of the width of activation and the depth of activation which is the net of scour and fill. Hence, the above equation can be modified to: Vj^ = Aa L (1-n) ... (2.3) where Aa = net area of activation (m^) For the solution of the above equations it is necessary to determine the porosity (n) of the bed material. The porosity is the ratio of the volume of voids to the total volume of the bed material. The term volume of voids refers to that portion of the volume of the material not occupied by gravel material. (Terzaghi and Peck 1967). Porosity should be determined by field tests at each particular site. However as the porosity of a natural deposit depends on the shape of the grains, uniformity of grain size and the conditions of sedimentation, for the purpose of this report a value of 30 percent has been adopted in all calculations. This represents the value of porosity for a typical mixed grain gravel deposit in its natural state. For example a glacial till with a very mixed grain size has a typical value of 20 percent whilst a mixed grain loose sand has a value of 40 percent. 27

2-5w5—Bed Load Discharge

Once all the necessary bed load data has been collected and analysed, the next important step is the combination with streamflow records to determine the bed load discharge.

Each of the monitoring sites chosen is in close proximity to one of the Department's streamflow gauging stations.For this project, the sites presented for illustration were chosen for analysis because the streamflow records were available up the date of the last field trip.

Armed with the bed load volume data and streamflow records, the remainder of this section identifies the methods used to determine the bed load discharge or if data requirements are not satisfied, other methods to permit comparison with other events.

Ideally, a site should be reset after each flood event in which the threshold of motion was exceeded. In this case, the scour/fill data, tracer movement, a^^ streamflow data for the event can be combined c^to^estimation'-^ bed load discharge. Combination with other~nmoni^tored events will lead to a bed load discharge v flow volume curve. Once this is established, the streamflow records for a particular year can then be examined and entered into the relationship to determine an estimate of the bed load discharge passing the transect.

However, as shown in the examples provided in the following chapters, this ideal case does not occur quite as often as one would expect or hope. Problems with scour chain stability, malfunctioning of the streamflow recorder, lack of adequate tracer recovery and most importantly, the inability to reset the site after each event due to both financial and labour commitments have been highlighted in

the overall progra-mJ to date.

For example, i!n the Numeralla site the data collected from Field Trip 1 was the result of two large independent flood events. Therefore, the combined effect only can be accepted as the scour chain information can not be separated. Any bed load volume calculated would be an underestimate and so only the distance moved against volume of flow can be analysed. This is also the case if the loss of scour chains prevents adequate information.

The analysis involves establishing a distance moved v flow volume relationship so that in future years, the volume of a flood can be used to predict overall movement of the bed. This can then be compared with other measured events to give an estimated volume of bed material.

It is appropriate to emphasise the importance of determining the threshold of motion for a particular site. All analysis is related to determining the duration of time the "start to move" flow was reached or exceeded, and the volume of flow to occur during this time. Therefore, as 28 suggested in Section 2.3.6 , a schedule of inspecting the site should be implemented so that this flow rate can be determined.

To date, this flow has not been established for any site in the program and as such the analysis of the data in the following chapters has been undertaken by assuming a value, or using a technique of examining duration v volume of flow to try and identify the threshold of motion for the site.

Each of the above techniques is discussed in more detail in the section devoted to detailed presentation of the results from each monitoring site. 29

WILSON RIVER 3.1 Site Location The Wilson River monitoring site is located on a gravel bar in a property called "Lamefield" upstream of Telegraph Point near Port Macquarie, on the Central Coast of NSW. It has a catchment area of 450 square kilometres.

Figure 3.1 shows the location of the site and the accompanying streamflow gauging station - Wilson River at Avenel (207014). As the gauging station was only established in May 1984, no meaningful average of annual flow can be made, however the average monthly flow is 22100 Ml. The gauging station has a catchment area of 505 square kilometres. Between the site and gauging station a few minor creeks enter the River. However, as the catchment areas are very similar, the gauging station will adequately record the flows which pass the monitoring site.

Site History The site was established in December 1987 with the set-up of 3 bench marks and survey of the base plan as shown in Figure 3.2. The transect is some 120 metres wide and was positioned across the widest section of the gravel bar. Both bulk volume and grid sample techniques were used to determine the size distribution of the bed material. Results of this analysis are shown in Figure 2.2. General observations of the site include the presence of established casuarinas on the right bank of the transect. On the lower part of the bar, young colonising casuarinas and scattered tall herbaceous vegetation have developed (Refer Figure 3.3). Four hundred metres downstream is a large pool where location of the tracers would be impractical at all times. A local landholder states that a considerable amount of gravel has moved onto the bar in the last five years. From inspection there are visible sheets of gravel with slip faces up to 0.4 metres high. For this site a total of 30 chains were installed using the excavator method. Figure 2.5 shows this method of installation. A total of 149 tracers were placed for Series 1, coloured light yellow. From December 1987 to the beginning of April 1988, the gauging station at Avenel showed that only low flows passed the monitoring site. However, throughout April, major flooding of the river occurred. Briefly, the flood FIGURE 3.1

WILSON RIVER

MONITORING SITE and GAUGING STATION LOCALITY PLAN Scale t 25000 FIGURE 3.2

WILSON RIVER BASE PLAN

TRANSECT

D/S X/S

0 20 40 60 80 100 m BM1 32 commenced on the 2nd April with an initial peak of 351 m^/s on the 4th. Recession commenced, however further floodwaters resulted in the major peak of 934 m^/s on the 7th. This peak receded rapidly until a further rise gave a peak of 308 m^/s on the 11th. A long recession resulted, until "normal" flows were returned on about the 24th April. A total volume of 179000 Ml passed the gauging station during this period.

The site was visited in June 1988 upon recession of the floodwaters. A summary of the results is given below, whilst details are presented in Section 3.3.

The flood resulted in the loss of 8 of the 30 chains placed. Average scour was 0.15 metres with the majority in the central part of the right bank between chains 18 and 22. Maximum scour recorded (of those still remaining) was 0.68 metres at chain 23. Average fill was 0.135 metres with an even spread over the entire transect. Maximiim fill of 0.29 metres occurred at chain 13.

Location of the tracers yielded only a 39 per cent recovery rate. A breakup of the transect gives that of the 43 tracers placed in the low flow channel only one was found. Presumably these are located further downstream in the deep pool. Against this, is the 67 per cent recovery rate of those placed on the lower right bank gravel bar between chains 3 and 13, however the average distance moved was only 5 metres with a range of only 0 to 21 metres. The vegetation cover would have influenced the movement in this area. Lastly for the upper part of the bar (from chains 14 to 30), a recovery rate of 39 per cent was achieved. From this section, the average distance moved was 64 metres with a much greater range from 0 to 185 metres.

Overall, the average distance moved was 26 metres. Combining this with the scour/fill data obtained, a bed load volume of 920 m^ is estimated as having passed through the transect.

Field observations give that the flood at the site was approximately bank full. Particles on the lower right bank bar near the low flow channel barely moved. This is thought to be due to the localised establishment of the young casuarinas which helped stabilise the bar and resulted in reduced velocities.

The dense vegetation growth on the gravel bar on the left bank upstream of the site, seems to have directed the flow towards the centre part of the transect, hence the loss of scour chains 14, 15, and 18 to 21, and the small proportion of particles found. These, as with those scattered in the low flow channel are expected to be located further downstream in the deep pool. co o z 2 < m ZD

H O 5 z o GO H m VJALE3

- I 34

The gravel on the bar after "^ppear^ to be of a larger grain size, as large partjlcles from to 400 mm on the a-axis were now scattered overthe

For the next series of tracers, the grain size distribution was altered to include more larger sized particles. The missing chains were replaced using the star picket method and the remaining chains reset.

The number of tracers was also increased to 253, due to the relatively low rate of recovery from the first series. This second series was coloured orange.

A further flood event occurred in early July 1988. This flood commenced on the 4th July and reached a peak of 743 Tcr/s on the 6th. Rapid recession followed, giving a total volume of 66000 Ml from the 4th to 12th July.

The site could not be revisited until September 1989. A dramatic change had occurred in the whole reach of the river. Field reports indicate that the previous low flow channel had scoured out to a depth of up to 2 metres. Gravel on the right bank bar had been deposited in depths varying from 0.5 to 2.0 metres. Previous low flow areas were now deep pools and the control bar downstream had been reduced dramatically. A Soil Conservation Service report also stated that one of the tracers was found some 1.5 kilometres downstream.

As a result of the striking channel changes which resulted from the July 1988 flood, the monitoring site was abandoned. It appears that on selection of this site, no account of the river's history of channel relocations had been taken.

This site has therefore highlighted the need to critically examine the location of any site with respect to general stability of the reach. Considering the money needed to set-up and continually monitor a site, the medium term (up to 10 years) stability of the reach must be guaranteed.

3 - 3 Detia 11 ed Results

This section provides details of the results obtained from the site. Due to the previously described abandonment of the site after the July 1988 flood, only the results from the field trip of June 1988 can be examined. However this analysis will permit illustration of the procedures used in detemining the bed load discharge for an event.

Table 3.1 shows the actual particles found and the distances moved, whilst Figure 3.4 shows the graphical location of the particles on the base plan. Included also, is the b-axis measurement of each of these particles. This has been used to examine if any relationship exists between FIGURE 3.4

WILSON RIVER - LOCATION OF SERIES ONE TRACERS - JUNE 1988

TRANSECT

0 20 40 60 80 100 m 1 < I I I 36

particle size and distance moved. This will be dealt with at a later stage.

Chain Particles Distances b-Axis No. Moved (m) (mm) 1

2 35 5 50

3 123 11 70 0 3 8 53 49 34 4 103 51 16 2 2 1 53 41 36 5 118 139 121 117 3 0 0 2 48 127' 431 46 6 142 105 3 13 84 53 7 77 2 63 75 3 3 3 5 42 39 41 34 8 4 34 122 4 7 8 68 54 57 9 93 32 120 94 10 6 6 3 42 31 54 45 10 15 115 25 5 7 10 49 49 39 11 97 9 61 146 12 8 9 6 47 39 36 62 12 53 24 148 10 3 1 41 37 68 13 91 141 46 28 2 2 1 21 43 88 36 43 14 106 135 6 58 54 58 15 96 0 42 16 17 18 19 20 21 143 80 142 167 52 45 22 23 21 111 129 185 48 61 24 48 10 128 63 105 115 44 41 57 25 110 50 43 26 130 7 66 0 78 96 43 35 34 27 19 70 53 28 20 125 0 12 51 48 29 69 0 41 30 47 79 2 6 35 40

Table 3.1 Wilson River - Series 1 Tracers - Located June 1988

From the table, the active and inactive zones of the transect during the flood are clearly shown, via the lack of data for those particles placed at chains 14 to 20 and in the low flow channel, and the large quantity of data from chains 3 to 13. This is also graphically shown in Figure 3.4. Note, in practice a much larger scale base plan was constructed and the actual number of each particle placed alongside its location to facilitate identification.

Scour/fill data is presented in Table 3.2. The method of taking the reduced level of the scour chains elbow and on the natural surface after the chains have been located and then reset has been used in this case. A graphic representation of the data is shown in Figure 3.5. WILSON RIVER - TRIP ONE 104.0 T BEFORE DURING AFTER 103.0 ..

102.0 .. e

97.0 ..

96.0 20 40 60 80 100 120 140 Chalnago (m) 38

From comparison of the total scour area and total fill area, the flood event resulted in a net loss of material from the gravel bar. Combining this data with the average distance moved of 26 metres, and using Equation 2.3 gives:

Volume of bed load moved (Vj^) :

Vj^ = Aa L (1-n) = 50.6 : 26 X (1-0.3) = 920 m- Table 3.2 Wilson River - Scour and Fill - June 1988

Chain Pre-Flood During After Scour Fill No. N.S (m) N.S (m) N.S (m) (m) (m) 1 2 97.528 97.761 0.000 0.230 3 97.928 97.776 97.906 0.152 0.130 4 97.961 97.934 98.052 0.027 0.118 5 97.941 97.950 97.974 0.000 0.024 6 98.056 98.007 98.000 0.049 0.000 7 98.174 98.094 98.202 0.080 0.108 8 98.252 98.225 98.261 0.027 0.036 9 98.236 98.202 98.246 0.034 0.044 10 98.311 98.151 98.306 0.160 0.155 11 98.348 98.201 98.269 0.147 0.068 12 98.259 98.181 98.241 0.078 0.060 13 98.181 98.103 98.396 0.078 0.293 14 98.332 98.566 15 98.720 16 98.521 98.375 98.699 0.146 0.324 17 98.697 98.489 98.673 0.208 0.184 18 98.760 98.714 19 98.885 98.804 20 99.059 98.849 21 99.126 98.823 22 99.286 98.854 23 99.477 98.798 99.015 0.679 0.217 24 99.617 99.051 99.125 0.566 0.074 25 99.764 99.328 99.409 0.436 0.081 26 99.929 99.750 99.786 0.179 0.036 27 100.036 100.156 0.120 28 100.469 100.311 100.451 0.158 0.140 29 100.971 100.919 101.010 0.052 0.091 30 101.216 101.216 101.229 0.000 0.013

Note, the area of activation of 50.6 m^ for this event was determined using the RATE Program which calculated the area of the transect below a stage height of RL 101.00 metres. A full description of the use of this program is given in Appendix B5.

An interesting analysis before we continue any further, is to examine if any relationship exists between particle size and distance moved. Figure 3.6 shows the plot of the b- 39 axis measurement for each of the particles found against distance moved. From the large scatter, no identifiable relationship appears to exist. For example, two particles numbered 21 and 111 were placed on chain 23. These particles have b-axis measurements of 48 mm and 61 mm respectively, however moved 129 metres and 185 metres respectively. This illustrates the lack of correlation between particle size and distance moved.

Following calculation of the bed load volume for this event, the streamflow records need to be examined to determine the rate of movement, that is, the bed load discharge.

This involves determining the duration of time during which the flow rate exceeded the threshold of motion of the site. From this a bed load discharge can be calculated and then this rate can be compared with flow volume passing the site.

Due to the limited availability of data for this site, no observations of the threshold of motion were undertaken. Therefore, a value will be assumed to permit illustration of the procedure.

The average distance moved for this event was only 26 metres. This indicates that the "start to move" flow was exceeded for a short time only.

Table 3.3 presents the duration and volume of flow which passed the transect when a base flow rate was exceeded. The duration and flow volume above a base flow rate is determined graphically by plotting the flood hydrograph. Duration is simply measured, while flow volume is calculated by determining the area under the hydrograph during this duration.

From examination of the rate of change of flow volume with duration, a marked change occurs between 600 and 700 m^/s. It would therefore appear that between these flow rates, the actual physical characteristics of the flow have changed, perhaps indicating that bed load movement has commenced.

For the purposes of this demonstration, the "start to move" rate will be adopted as 600 m^/s. This flow was equalled or exceeded for 17.6 hours, and a flow volume of 45760 Ml passed the site.

Bed load discharge is therefore the volume moved in the time this flow rate was exceeded. That it, an estimate of the bed load discharge for this event is:

^^ = 9^0/17.6 =52.3 m^/h FIGURE 3.6

PARTICLE SIZE v DISTANCE MOVED

WILSON RIVER - SERIES ONE - TRIP ONE

200

150

(n 100 X< OQ

50

HKH ** t —,— —I —T-* 100 50 150

DISTANCE MOVED (M) 41

This then would become the first point in a bed load discharge v flow volume relationship, which if the site was continually monitored, could be used to determine the rate of bed load movement in a given year from a known volume of flow. Table 3-3 Duration and Volume Above a Base Flow Rate April 1988 Flood - Wilson River Above Flow Duration Volume (m^/s) (h) (ML) 900 2.8 9073 800 6.0 19152 700 8.4 26352 600 17.6 45760 500 20.0 50400 400 23.6 56160 300 32.4 63360 42

4. NKVER NEVER RIVER

4-1 Site Location

The Never Never River site is located just above its confluence with the Bellinger River on the property called "Neverend" near the township of Bellingen on the mid North Coast.

As shown in Figure 4.1, the monitoring site is located downstream of the gauging station at Glenniffer Bridge (Station Number 205014). The station and site have catchment areas of 51 and 95 square kilometres respectively- due to two tributaries. Buffers Creek and Stony Gully entering the River between the two locations.

Depending on the physical characteristics of the tributaries, flow conditions at the site may not be adequately represented by the flow recorded at the station. For example, storm conditions could cause flooding only in the tributaries and movement of the tracers may occur even though little flow is recorded at the station. Therefore, this aspect must be kept in mind when examining the streamflow records for this site at present. In the long term, if the bed load site is continued to be monitored, it may be beneficial to move the gauging station to a location downstream of the site to allow full flow to be recorded. Alternately a monitoring system comprising of a sensor and logger could be installed at the site to measure the stage height throughout a flood. From this, a flow volume and rate can be calculated. Nevertheless, the gauging station at Glenniffer is the only source of streamflow information at this time. It has only recently been established (May 1982), and whilst only a short length of record in terms of obtaining any reliable statistics, in this time, the average monthly flow is 6395 Ml whilst since the monitoring site has been established, (February 1988), the monthly average has been 14590 Ml.

4 - 2 Site History

The monitoring site was established at the downstream end of a gravel bar with an average width of 20 metres, as shown in Figure 4.2. Three bench marks were placed, however Bench Mark 1 is located some 50 metres downstream of the transect due to the dense growth of trees on both banks at the site as shown in Figure 4.3. FIGURE 4.1

NEVER NEVER RIVER

MONITORING SITE and GAUGING STATION i LOCALITY PLAN Scale t 25000 FIGURE 4.2

NEVER NEVER RIVER BASE PLAN

D/S X/S

Q BM1

TRANSECT

20 40 60 80 100 45

The transect is about 50 metres wide and contains a total of 14 chains. Again, both bulk volume and grid sample techniques were used to determine the size distribution. Also, a bulk density and water absorption test was undertaken on the gravel sample.

The bulk density for the coarse aggregate in the natural bed material was measured at 2630 kg/m^ (oven dry) and 2660 kg/m^ (saturated surface - dry basis). Water absorption of the particles was then only 1 per cent.

General observations of the site include the dense lining of vegetation on both banks together with the planting of the gravel bar upstream by herbaceous vegetation. The reach has shallow water covering the entire channel downstream which is unlikely to become dry. Recovery but not location of a particle may be a problem.

For this site, the scour chains were installed using the star picket method. Figure 2.6 shows this method of installation. A total of 139 tracers were placed for Series 1, coloured pink.

From February to late March 1988, low flows were recorded at Glenniffer Bridge. A flood event however commenced on the 1st April consisting of four peaks, the largest peak of 150 m^/s occurring on the 6th April. Slow recession resulted in "normal" flows returning about the 19th April. During this time, a volume of some 407 00 Ml passed the gauging station.

On return to low flows, the site was revisited on the 23rd May 1988. A summary of the results follows, with actual details given in Section 4.3.1.

For this flood event only one scour chain was lost. Average scour was 0.140 metres with chains 6 to 14 generally above this average. Chain 6 had the maximum scour of 0.21 metres. Average fill over the transect was 0.270 metres, with chains 3 to 6 averaging above 0.33 metres. Maximum fill of 0.375 metres occurred at chain 4.

Re-location of the tracers gave a 54 per cent recovery rate for the entire transect. Breaking up the transect into the low flow channel (chains 1 to 9) and the right bank gravel bar (chains 10 to 14), gives recovery rates of 50 and 68 per cent respectively. It appears that the vegetation cover gave a degree of stability to the gravel bar as average movement of the two zones contrasts markedly. The particles originally located in the low flow channel averaged 125 metres movement downstream with a range of 0 to 275 metres. The gravel bar tracers averaged only 58 metres with a similar range from 0 to 215 metres.

Overall, the average distance moved was 106 metres and combining with the scour/fill data aives a bed load volume moved by this flood event of 1380 m .

O z o co m • • " 47

No marked change was observed in the si^_jiistribution of the newly deposited gravel, so the secbn^ ¿Sries of tracers was kept with basically the same distribution as the first. Lack of time however, prevented the resetting of the site at this time. This was carried out in June 1988 when next in the area.

In the meantime, a small flood event occurred in early June 1988 which caused slight movement of the Series 1 tracers that were located on the surface near the transect. The flow causing the movement would have given an indication of the threshold of motion for this site.

The second series of tracers (totalling 152) were placed and the chains reset. Subseguent checking of the gauging station records to identify this "start to move" flow, showed the recorder had malfunctioned. Unfortunately, no meaningful data could be gleaned from the charts regarding flow volume.

This examination of the flow chart also identified the loss of streamflow data from late May 1988 to mid-September 1988. From other sources, such as daily river reports for nearby rivers, two further flood events occurred during this time, however due to lack of funds, no field trips could be undertaken to collect the field data.

Finally in December 1988, sufficient funds were made available to reset the site. However, because of the recorder malfunction, no analysis could be undertaken. The primary purpose of this trip therefore, was to reset the site so that the locations of the tracers as of December 1988 could be noted, and hence become the new origin for all future events.

The following statistics summarise the data gathered on this trip. Of the Series 1 tracers, 65 per cent were recovered with a breakup between low flow channel and gravel bar zones giving recovery rates of 62 and 74 per cent respectively.

Distance moved is immaterial, however for interest sake, the average movement for Series 1 tracers since placement was 170 metres (range 0 to 357 metres) compared with 106 metres from placement to Trip 1 and a range of 0 to 275 metres.

For the Series 2 tracers, the overall recovery rate was a high 78 per cent with a similar breakup of 76 and 83 percent between the two zones of the transect. The increase in recovery rate can basically be attributed to better understanding in the use of the detectors, and the low flow rates at the time of this trip allowing all areas to be searched easily.

The Series 2 tracer movement whilst again immaterial due to the lack of flow data can be summarised as: average distance moved was 108 metres overall (compared to only 64 48 metres for Series 1 tracers during the same time),with a range between 0 to 332 metres.

The difference in average distance moved between these two series highlights the effect of the tracers becoming intermixed in the natural bed material after a flood event. The Series 1 tracers, after location in the first trip were replaced at the depth found, whilst the Series 2 tracers were basically loose particles.

Therefore, it appears that the data relating to the movement of a series of tracers after their first event may not be truly representative of the actual bed load movement, as the particles are not intermixed with the bed material. Upon collection of a good number of samples in future events, this initial data may need to be disregarded.

As no flow data was available, the scour/fill data is irrelevant, however the success of the installation method was again highlighted by the loss of only one chain. The site was then reset and Series 3 tracers placed on the transect. This series was coloured orange and consisted of 122 tracers.

A small flood event occurred in mid December 19 88 ,however a volume of only 14600 Ml passed the site with a peak of 133 m^/s. This may have caused some movement of the tracers however due to very tight financial constraints, the site was not revisited.

Low flows occurred throughout the start of 1989 until mid- March. A flood event commenced on the 25th March, consisting of two peaks. The largest of the peaks, 214 m^/s occurred on the 2nd April. The total volume of flow passing the site from the 25th March to the 7th April was some 28000 Ml.

Before suitable low flows could permit a successful field trip, another flood event occurred commencing on the 23rd April 1989. Flow records for this flood show a very fluctuating volume, however it basically consisted of two flood peaks, the largest of 220 m^/s occurred on the 26th April. The volume of flow from the 23rd to the 29th April exceeded 30000 Ml.

The site was visited for the third time in early May 1989. Including all series of rocks (413 tracers), only 55 tracers could be found, namely 16, 13 and 26 from Series 1, 2 and 3 respectively. The low number of tracers found can be attributed to two factors. Firstly, the flow at this time was some 200 Ml/day. Combining this with the scour that had taken place in the previous flood events, caused the pools downstream to be too deep for thorough searching.

Field notes reveal that the flood activity during April 1989, caused a new deep pool about 100 metres downstream of the transect. Several other pools at approximately 175 to 49

250 metres, 350 to 400 metres and at 500 metres downstream were also too deep to search, thus reducing the number of tracers found.

The following section summaries the limited data available for each series. Average distances moved downstream were 180, 260 and 334 metres for Series 1, 2 and 3 respectively, giving a total average distance of 285 metres.

The influence of intermixing of the tracers with the bed material is again highlighted by the above data.

Very limited scour/fill data is also available, as the flood activity in April resulted in a loss of all nine chains within the low flow channel.

A comparison of the total flow volume in April 1989 of 58500 Ml with the average monthly flow of 6395 Ml and an average April flow volume of 19000 Ml highlights the severity of the flooding during this month.

The site was reset installing new chains using the star picket method. Note however, that chains 1 to 5 could not be installed due to the proximity of the bed rock. This location would be the ideal case for the suggested bolt to bed rock method of installing scour chains as discussed in Section 2.3.4.

The next series of tracers, coloured red had a greatly reduced number (60). It was considered that in combination with the previous series, the site now had sufficient numbers of tracers to permit a reasonable statistical estimate of the bed load movement. If more were added to the site, the reach immediately downstream of the transect could become saturated and because of time constraints would limit a thorough search of the area to that near the transect and not throughout the entire reach which yields more meaningful results.

No further flood events have occurred to date.

4.3 Detailed Results

This section provides details of the results obtained from the Never Never River site to date. Details for each reset trip will be presented separately to illustrate the different types of analyses depending on data availability.

4.3.1 Field Trip 1 - May 1988

As mentioned previously, only one flood event occurred during the time between initial site set-up and this field trip. Therefore, the results can be analysed with the streamflow records of this flood to determine a bed load discharge.

Table 4.1 shows the actual tracers relocated after the flood of April 1988 giving an average distance moved of 106 50 metres, over the entire transect.

The flood at the site caused the majority of the transect to be activated as shown by the spread throughout chains 1 to 14. Scour and fill data is presented at Table 4.2. A graphic representation produced using the TRANS program is given in Figure 4.4.

For demonstration purposes, the methods of determining the area of activation as described in Section 2.5.3 will be presented below.

Firstly, the reduced level method involves averaging the amount of scour and fill which occurred between each chain, multiplying by the distance between the chains, and summing to give the scour and fill area. Adding the absolute values gives the net area of activation.

For example. Table 4.2 shows that at chain 1, scour of 0.075 metres and fill of 0.252 metres occurred, and at chain 2, 0.094 and 0.284 metres respectively. The distance between these two chains from previous surveys is 2.0 metres. Therefore, the areas scoured and filled between these chains are:

Scour Area: S = 0.5 (0.075 + 0.094) 2.00 = 0.17 m^

Fill Area: F = 0.5 (0.252 + 0.284) 2.00 = 0.54 m^

Similar calculations can be done for each of the remaining chains. Summing gives a scour area of 5.1 m^ and a fill area of 12.5 m^. Therefore, the net area of activation is 17.6 m^.

The other method is by use of the RATE program which compares the cross sectional area of the transect before, during and after the flood below a user-defined stage height. This stage height should be chosen so that it is above the level at which any action has taken place, and at a level that confines the section to the area surveyed in all three stages. Examination of Figure 4.4 shows a stage height of RL 97.50 metres satisfies the above conditions. The RATE program then gives: At RL 97.50m: fy Original area = 12.2 m ....1 During area = 79.1 m ....2 After area = 67.4 m^ 3 2 Scour Area =2 - 1 =6.9m ....4 Fill Area =2 - 3 =11.7m ....5 2 Net Area =4 + 5 =18.6m 51

Table 4.1 Never Never River - Series 1 Tracers - Located May 1988

Chain No. Particles Found Distance Moved(m)

1 88 121 47 127 28 0 0 0 0 0 30 72 138 130 3 18 0 24 0 220 2 135 96 4 0 59 70 116 10 62 264 220 0 5 177 3 120 0 36 109 64 275 125 260 4, 61 89 11 195 204 232 Dc 97 110 53 50 250 128 243 248 6 17 140 35 20 23 52 66 247 194 152 17 14 7 104 4 43 108 56 57 192 246 272 264 8 48 75 58 37 0 0 3 188 111 86 68 44 238 245 219 203 9 5 123 239 127 9 16 100 125 38 239 4 139 75> 7 10 92 22 179 137 77 129 54 46 '4 3 8 11 132 51 112 180 215 28 12 32 105 91 114 69 18 3 5 13 137 29 13 83 34 6 19 57 137 13 14 102 106 82 55 7 0 15 :2 5

Table 4.2 Never Never River - Scour and Fill - May 1988 Chain Pre-flood During After Scour Fill No. N.S. RL N.S. RL N.S. RL (m) (m) (m) (m) (m)

1 95.039 94.964 95.216 0.075 0.252 2 95.178 95.084 95.368 0.094 0.284 3 95.255 95.171 95.533 0.084 0.362 4 95.261 95.164 95.538 0.097 0.374 5 95.357 95.207 95.492 0.150 0.285 6 95.362 95.154 95.459 0.208 0.305 7 95.294 95.165 95.429 0.129 0.264 8 95.274 95.175 95.435 0.099 0.260 9 95.429 95.267 95.506 0.162 0.239 10 95.503 95.364 95.643 0.139 0.279 11 95.617 95.429 95.662 0.188 0.233 12 95.788 95.626 95.805 0.162 0.179 13 96.090 95.891 96.158 0.199 0.267 14 96.687 95.542 96.754 0.145 0.212 NEVER NEVER RIVER -- TRIP 1 100.5 _ BEFORE DURING 100,0 AFTER

99.5

g >

O UJ

H 30 40 60 ChQinage (m) 53

Both methods yield very similar results and because of its efficiency and speed, the RATE program method is recommended for use.

Comparison of the total scour and fill for this flood showed a net gain of material to the gravel bar. Combining this scour/fill data with the average distance moved of 106 metres, the volume of bed load material moved is:

Vj^ = 18.6 X 106.0 X (1-0.3) = 1380 m^

For the calculation of bed load discharge, it is again essential to have determined the threshold of motion for the site. As mentioned earlier, site observations identified this flow rate but unfortunately the recorder malfunctioned at this time preventing measurement of this vital information.

Examination of the data in Table 4.1 shows the tracers moved an average 106 metres with a range of 0 to 275 metres in this flood. This suggests that the duration of time above the threshold of motion was considerable or the actual velocities reached during the flood were high enough to move the particles a considerable distance over a short time. Table 4.3 Duration above a base flow rate - April 1988 Flood - Never Never River Abov^1 Flow Duration (m-Vs) (h)

140 2.0 130 4.8 120 6.8 110 8.0 100 10.4 90 17.6 80 27.6 70 40.8 60 50.0 50 55.2 40 65.2 30 97.2 20 186.0 10 312.4

One method of discerning between either high velocities or long duration requires a peak flood level to be recorded during the event at the site. This would allow calculation of the total cross sectional area and hence the peak velocity. Examination of this velocity would assist in determining if movement was based on high velocities or duration. Unfortunately no flood level was noted during this trip. 54

As in the Wilson River example, another method is to examine the flood hydrograph, in particular the duration of time in which a flow rate is exceeded. Table 4.3 details the durations for this flood. This shows that from 60 to 70 m^/s, the rate of change alters, indicating perhaps that the velocity of flow has changed, possibly because of the movement of bed material.

If we assume 60 m^/s as the threshold of motion at this time, the bed load discharge for this event is 27.6 m^/hr. Against this, is the flow volume of 15870 Ml which passed the gauging station in the 50 hours the threshold flow was exceeded.

4-3-2 Field Trip 2 - December 1988 As mentioned in the summary of this trip, several flood events were experienced at the site before funds permitted the site to be re-set. More unfortunate was the malfunction of the recorder, preventing a continuous streamflow records for the site. No further analysis of the collected data can be undertaken due to this lack of streamflow data.

Table 4.4 Never Never River - Series 1 Tracers - Located December 1988 Chain Particles Located Distance Moved Since No. Placement (m) 1 121 127 28 0 0 0 72 3 19 138 130 246 252 114 232 17 2 135 76 113 96 15 67 226 55 155 148 116 103 70 0 159 308 3 12 120 0 1 25 36 109 64 139 285 255 288 4 99 6 85 31 13 287 219 186 87 117 79 89 11 182 158 317 261 265 5 134 4 1 172 151 347 97 95 110 53 50 45 313 151 335 97 346 359 6 17 41 93 14 2 192 220 263 242 113 126 23 235 224 7 40 63 144 277 131 56 120 330 8 75 58 148 177 111 67 86 44 344 353 307 357 9 49 123 69 0 174 214 9 16 78 100 128 125 38 159 97 185 334 168 75 63 10 92 8 179 127 139 77 81 129 54 225 135 190 192 83 11 51 42 112 249 151 97 12 32 105 114 100 144 170 13 137 29 13 34 35 137 113 23 14 102 122 106 82 55 10 5 0 33 145 55

Therefore, the particle locations as shown in Tables 4.4 and 4.5 are presented to show the origin of Series 1 and 2 tracers for all future events.

Table 4.5 Never Never River - Series 2 Tracers - Located December 1988

Chain Particles Located Distance Moved Since No. Placement (m)

114 27 36 128 0 0 0 0 1 25 134 135 45 58 139 0 0 0 0 0 0 149 67 69 60 17 2 2 321 116 0 2 146 150 110 148 98 32 52 4 0 171 50 138 136 111 142 24 6 54 3 66 35 120 41 33 0 2 220 123 119 106 222 199 110 4 33 142 129 85 90 129 220 150 264 118 61 151 131 127 84 133 245 190 5 88 108 141 144 54 260 123 18 222 146 68 113 9 125 191 8 6 100 62 53 325 127 125 21 37 121 147 254 332 239 171 7 72 23 32 43 132 140 257 193 195 122 122 57 92 165 160 127 8 125 63 124 89 75 55 95 125 97 105 87 52 64 180 280 153 9 51 117 116 93 8 165 257 88 128 35 118 7 79 89 130 216 10 101 107 42 1 165 250 60 125 145 20 10 39 38 65 222 102 240 164 11 74 6 102 97 94 109 27 213 204 132 90 182 26 18 44 60 22 61 12 73 24 95 3 11 126 142 83 52 74 27 131 78 77 99 49 33 70 13 15 84 104 29 23 88 4 5 29 47 8 0 0 222 14 22 65 14 115 49 34 0 0 0 0 193 0

4.3.3 Field Trip 1 - Mav 1989 Between field trips, three flood events which would be expected to exceed the threshold of motion for the site were experienced. Therefore, as discussed in Section 2.5.4, a distance moved v flow volume analysis can only be undertaken for this field trip. Tables 4.6 to 4.8 detail the movement of the tracers from placement to this field trip. Note, in Table 4.6, the overall movement of the Series 1 tracers since set-up is listed. However, because of the loss of streamflow records between Trips 1 and 2, this information can not be analysed by itself. The difference between the overall distance and that moved up to Trip 2 gives the movement between Trips 2 and 3. 56

Table 4.6 Never Never River - Series 1 Tracers - Located May 1989

Chain Particles Distance Distance at Distance No. Located Moved Since Trip 2 Moved Placement (New Origin) Between (m) (m) Trips 2 & 3 (m) 1 88 121 372 161 NF 0 NF 161 2 70 62 455 552 308 NF 147 NF 3 46 448 NF NF 109 435 255 180 4 39 181 NF NF 5 6 41 530 220 310 7 56 108 592 424 330 NF 262 NF 8 37 521 NF NF 9 38 125 63 62 10 11 42 415 151 264 12 114 477 170 307 13 137 144 35 109 14 106 0 0 0

Note: NF denotes particles not found in the particular field trip. Streamflow records between Trips 2 and 3 can be summarised as: Flood Dec 88 Early Apr 89 Late Apr 89 Volume (Ml) 14600 28178 30585 Duration (h) 152 310 138 Peak Rate (m^/s) 133 214 220

Table 4-9 Flood details for Never Never River between Trips 2 and 3. 57

Table 4.7 Never Never River - Series 2 Tracers - Located May 1989

Chain Particles Distance Distance Distance No. Located Moved Since Moved Up To Moved Placement Trip 2 Since (m) (m) Trip 2 (m) 96 284 NF NF 1 60 590 116 474 2

3 66 41 467 296 38 220 429 76 4 90 284 118 166 61 451 84 367 5 88 387 260 127 6 7 8 9 30 445 NF NF 10 20 586 222 364 11 12 77 263 33 230 13 12 0 NF NF 14 22 49 289 271 0 193 289 78

Again, analysis of the records is made difficult because of the lack of a confident threshold of motion value. Field Trip 1 data indicates a value of 60 m-^/s, but this is a rough estimate only and may only be applicable for the condition of the gravel bar at that time. Since several further floods have occurred, an examination of the duration times above a base flow rate was performed to determine if any trend exists. Figure 4.5 shows the plot of duration of time above a base flow rate against the base flow rate for all floods since set-up. The December 1988 flood shows a similar reversal in rate of change between 60 to 70 m^/s, as with the April 1988 flood. However, in the early April 1989 flood this does not occur 58 until 100 to 110 m^/s. In the late April 1989 flood, a minor change occurs between 40 and 50 m^/s. Table 4-8 Never Never River - Series 3 Tracers - Located May 1989

Chain No. Particles Distance Moved Since Located Placement (m) 1 36 285 2 85 204 3 54 374 89 474 4 8 131 395 402 86 366 5

6 58 573 7 140 423 21 568 8 91 241 9 147 423 10 112 146 32 0 249 267 98 465 11 68 508 12 35 42 132 0 287 278 96 23 443 365 13 37 49 0 370 22 126 431 281 14

It would appear that the estimate of 60 m^/s is at least in the right vicinity. It should be remembered that as displayed in the Wilson River Site, vegetation plays a significant influence on the movement of bed material. In the case of the early April 1989 flood, the establishment of vegetation since the previous flood may be the cause of the higher indicator, whereas the lack of vegetation cover immediately after would explain the lower indicator for the late April 1989 flood. Therefore, the estimate of 60 m^/s will be adopted for Field Trip 3 data. From the flood hydrographs, the volume of flow passing whilst this base rate was exceeded is given in Table 4.10. FIGURE 4.5

DURATION ABOVE A BASE FLOW RATE FLOODS IN THE NEVER NEVER RIVER

300

230

200

150

100

FLOW RATE (cumecs) 60

Flood Dec 88 Early Apr 89 Late Apr 89 Total Duration (h) 23.4 18.4 46.4 88.2 Volume (Ml) 7697 7553 21110 36360

Table 4.10 Duration and Volume Above Threshold of Motion for Floods in Never Never River Trips 2 to 3. An average distance of 285 metres can be calculated for all three series of tracers, resulting from a total flow volume of 36360 Ml which occurred whilst the threshold of motion value was exceeded.

4.3-4 Summary From the data collected, analysis has shown: i) Threshold of motion of 60 m^/s is apparent, dependent however on the vegetation cover existing. ii) Field Trip 1 data gives a bed load discharge of 27.6 m^/h for a flow volume of 15870 Ml. For use in conjunction with Field Trip 3, this volume resulted in an average movement of 106 metres. iii) Lack of streamflow data prevents analysis of Field Trip 2 data. The locations of tracers at this trip become the new origin for all subsequent trips. iv) Field Trip 3 data gives an average distance moved of 285 metres for a combined flow volume of 36360 Ml above the threshold of motion of 60 m^/s. V) Only two points have been established to date for the distance moved v flow volume relation, and therefore no further analysis can be undertaken until further data is available. 61

RTVTgP

5»! Site Location The Numeralla River is a tributary of the Murrumbidgee River. The monitoring site is located at the township of Numeralla near Cooma just downstream of its confluence with the Big Badja River.

Figure 5.1 shows the location of the site, just downstream of the gauging station at Numeralla School (station number 410062). Unfortunately, the site chosen is below the confluence with the Big Badja River, whilst the gauging station is upstream.

The catchment area of the site is 915 square kilometres, compared with only 673 square kilometres for the gauging station. Therefore, variations may occur at this site depending on the catchment area contributing to the flood. For example, a stoinn may only cause flooding of the Big Badja River and hence cause movement of the tracers whereas the Numeralla River may only have minor flow. The gauging station in this case does not provide an adequate record of the flow at the site.

Therefore, care must be exercised at this site in the analysis stage. If the monitoring program continues in the long term, it is recommended that a permanent gauging station be located downstream of the Big Badja River confluence, so that all flows passing the site can be recorded. As with the Never Never River site, installation of a monitoring system consisting of a velocity sensor and logger should be investigated.

Site History The monitoring site was established in February 1988 and is located at the upstream end of a gravel bar approximately 60 metres wide. Two bench marks were set up and used to survey the base plan as shown in Figure 5.2. The transect is about 9 0 metres wide, and required the installation of 15 chains for adequate coverage. At this site, only a grid sample technique was used to establish the size distribution of the tracers based on the natural bed material. General observations of the site include the extensive cover of herbaceous vegetation over the gravel bar and the coarseness of the particle size in comparison with the two previous sites examined, as shown in Figure 5.3. However a sub-surface visual inspection reveals coarse gravel mixed with about a 50 per cent sand content.

A total of 150 tracers were placed for Series 1, coloured pink. FIGURE 5.1

NUMERALLA RIVER

MONITORING SITE and GAUGING STATION

LOCALITY PLAN Scale 1: 25000 FIGURE 5.2

NUMERALLA RIVER BASE PLAN

D/S X/S

QBM2

gbmi TRANSECT

10 2 0 3 0 4 0 50f n 64

From set-up in February, to the end of April 1988, low flows were experienced. On the 29th April a rise in flow rate commenced, resulting in an initial peak of 144 icr/s. Further inflow created a second and larger peak of 206 m^/s on the 30th. A total volume of over 30000 Ml passed the gauging station from the 29th April to 6th May.

High base flow continued throughout May and June until a further flood event occurred in early July before the site could be reset. This second event commenced on the 5th July reaching a peak of 366 m^/s on the 6th. A volume of 25500 Ml passed the gauging station until the 15th July. High base flow continued throughout August until the site was revisited on the 1st September.

A summary of the results from this first field trip is given below, and details are provided in Section 5.3.1.

The two flood events did not result in the loss of any scour chains. Measurements from the chains can not separate the activity during each flood, so no details will be provided. However scour was recorded evenly over the entire transect whilst the majority of fill occurred in the low flow channel section between chains 1 and 3. Only minor movement (both scour and fill) was measured between chains 6 and 8, highlighting the inactivity of this part of the gravel bar.

Recovery of the tracers was 56 per cent of the total placed. A breakup of the transect indicates that only 18 per cent of the tracers placed in the low flow channel were recovered, and on the lower section of the bar (chains 4 to 7) some 53 per cent were found. The upper zone of the gravel bar saw a recovery rate of 79 per cent.

Presumably, the low flow channel tracers are located further downstream than could be searched in the time available during the field trip. This is highlighted by a comparison of the average distance moved of tracers placed in the three zones. The low flow channel tracers moved an average distance of 88 metres with a range from 0 to 363 metres. Against this is the average distance of only 23 metres (range 0 to 161 metres) for the lower gravel bar section, and 48 metres (range 0 to 370 metres) for the upper gravel bar zone. The vegetation cover is thought to have influenced the movement in the lower zone. The greater distance moved in the upper zone is due to a small high level floodrunner near the right bank which in flood events allows easy movement along this path.

Overall, the average distance moved was 45 metres. However, as the site could not be reset after the first event, the scour and fill information for each event cannot be m >D

> < m D

H O z o (/) H m

T1 O c 33 m U• 1 co 66 separated. A s such no accurate measure of the bed load volume can be obtained.

For the next series of tracers, a total of 150 particles was again used, this time coloured yellow. A similar size distribution was used for the selection of the tracers, as no marked change was observed in the size distribution of particles on the gravel bar after the flood activity.

The flow rate passing the gauging station continued to fall throughout September 19 88 until a small event occurred from the 17th to the 27th with a peak of 76.6 m^/s. Thi s resulted in a volume of 13100 Ml. A long recessio n occurred throughout October and November until a further flood event commenced on the 17th November. A total volume of some 8800 Ml passed the gauging station with a peak of 215 m-^/s . Rapi d recessio n followed , however , hig h fluctuations in flows throughout the remainder of the year and into January and February 1989 prevented a revisit to the site. Limite d finances at this time also required a guarantee of a successful recovery trip.

In mid March 1989 high flows again occurred. A rise in flow rate commenced on the 14th producing a peak of 62.5 m^/s and a total volume to the 20th of 7285 Ml.

Moderate flood activity followed with two events occurring in April. From the 1st to 9th April a flow volume of 16700 Ml passed the gauging station at a peak rate of 78 m"^/s, whilst from the 9th to 17th some 19000 Ml of flow was measured at a peak of 109 m^/s.

High base flows continued throughout May again preventing a field trip to reset the site. Agai n in June, a further small event resulted in 4200 Ml passing the station at a peak rate of 30.2 m^/s.

Finally, in early July "low" flows permitted the site to be revisited on the 13th. Of the combined 300 tracers placed at the site, a total of 132 were relocated. This consisted of 59 tracers from Series 1 (39 per cent) and 73 tracers (49 per cent) from Series 2.

The following summairy is provided below while full details are available in Section 5.3.2. Floo d activity over the previous eight months resulted in the loss of four scour chains, but any measurement of scour and fill would be meaningless, a s th e sit e wa s no t rese t afte r eac h independent flood event. Examination o f th e trace r movemen t however , ca n b e undertaken as it can be compared with the volume of flow in all the events. Fo r Series 1 tracers, only 39 per cent were recovered with a breakup of 5, 29 and 64 per cent for the low flow channel, lower and upper zones of the gravel bar respectively. Agai n tracers placed in the low flow channel have a very low recovery rate. Thi s is due again to the limited time to search far enough downstream and the 67 difficulty in recovering a particle in water deeper than about 0.5 metres.

No similar trend in distance moved throughout the transect was found in this trip to that in Trip 1. Tracers in both the lower gravel bar zone (chains 4 to 7) and the upper zone (chains 8 to 15) moved an average of 18 metres since the previous field trip. This gives a total average distance for all Series 1 tracers of 66 metres since placement.

Series 2 tracers had a 49 per cent recovery rate with a similar zone breakup of 57,38 and 51 per cent respectively. The high channel recovery rate can be attributed to the limited distance moved with an average of only 4 metres and a range of 0 to 12 metres.

Whilst numerous flood events occurred between visits, very limited movement of the gravel bar has occurred. Series 1 tracers showed an average movement of only 18 metres. Series 2, only 8 metres.

This comparison is interesting, as in other sites examined it is apparent that the movement of "loose" tracers, that is, when initially placed was greater than any previous series which had become intermixed with the natural bed material. However at this site, the Series 1 tracers were moved further, although only slightly. One account could be the size of the particles at this site which was mentioned before as being coarser than other sites.

Another interesting comparison is the lack of movement in the upper zone of the gravel bar. In the previous trip, the majority of particles placed in this zone moved an average of 48 metres (range 0 to 37 0 metres). Only 8 particles did not move. However in the Series 2 tracers, an average of only 12 metres was found (range 0 to 7 6 metres) and 18 had not moved, especially near chains 14 and 15. This is the location of the floodrunner near the right bank.

It therefore appears that, although considerable flood activity occurred between trips, these floods were not of sufficient height and volume to commence the floodrunner flowing, hence the resulting lack of movement in this zone.

A comparison of the flow volumes and peak rate, as shown in Table 5.1 supports the above conclusion. 68

Flood Volume Duration Peak (Ml) (h) (m^/s) April 88 33065 190 206 July 88 25450 212 366 Sept 88 13180 254 76.6 Nov 88 8865 100 215 March 89 7285 160 62.5 Early Apr 89 16765 214 78 Late Apr 8 9 19000 194 109 June 8 9 3094 55 30.2

Table 5.1 Flood Details for Numeralla River Site The flood events prior to Trip 1 (April '88 and July '88) were of much greater volume and peak flow rate than the events since.

The bed load movement data to date therefore gives a good range of conditions. Ideally, to establish the bed load - streamflow relationship at the site, events of different magnitude are required to be monitored. The site was reset installing new chains where applicable using the star picket method. The next series of tracers, coloured red and numbering 128 were placed. Note however, that the chains numbered one and five could not be installed due to the proximity of the bed rock. This site seems suitable for the use of the bolt to bed method of chain placement.

5,3 Detailed Results The following section provides the actual data collected and the results of the analysis of this data. As two field trips have been undertaken, each will be presented separately. 5.3.1 Field Trip ] - September 1988 As mentioned in Section 5.3.2, two independent flood events occurred from set-up to the first field trip. Both are expected to have caused some movement of the bed material. Therefore, the data for this trip can only be analysed for a distance moved v flow volume relationship. Table 5.2 presents the tracers located in this trip, giving an average distance moved of 45 metres. No physical determination has been made to date in identifying the "start to move" flow rate at this sitey therefore the analysis will be similar to that undertaken previously for the other sites. 69

Table 5.2 Numeralla River - Series 1 Tracers - Located September 1988.

Chain Particles Located Distance Moved No. Since Placement (m) 1

2 303 291 20 45 286 46 3 398 261 6 106 309 357 30 363 4 321 254 360 7 5 19 348 315 0 112 5 243 397 313 359 274 12 1 9 8 6 308 269 373 0 161 0 6 363 383 354 0 52 9 283 245 65 0 7 393 0 137 0 8 343 278 276 335 0 0 15 0 367 316 0 67 9 355 297 371 400 345 0 0 0 106 0 287 356 63 67 10 282 310 337 272 0 25 76 84 362 280 143 228 11 394 306 347 0 25 124 395 369 262 346 72 62 131 188 12 256 396 341 300 45 43 50 13 342 246 44 370 13 266 377 257 273 43 199 45 12 298 334 366 295 5 14 88 101 14 292 271 351 358 247 0 3 16 87 10 301 275 387 296 14 0 0 7 15 270 365 241 361 6 0 8 7 304 299 290 317 0 3 3 0

From an examination of the flood hydrographs for these floods, the duration above a base flow rate is given in Table 5.3. Above Flow April 1988 July 1988 (m^/s) Duration (h) Duration (h) 350 _ 1.6 300 - 6.0 250 - 8.4 200 2.0 10.5 150 18.4 12.8 100 32.4 16.8 50 41.4 25.6

Table 5.3 Duration above a Base Flow Rate - Numeralla River Floods from Set-up to Trip 1. 70

In the April 1988 flood, a marked change in rate of increase of duration occurs at 40 m^/s and again at 100 m /s. For the July 1988 flood, this change occurs at 80 m /s. Examination of the data in Table 5.2 shows the tracers moved an average of 45 metres with a range of 0 to 370 metres. This suggests that the actual time the flow rate was above the threshold of motion was considerable, and therefore the threshold value is more likely to be about 100 m-^/s. The effect of vegetation is again shown by the lower value for the flood in July 1988, as any vegetation cover would have been removed by the previous flood, and would not have had sufficient time to re- establish.

Therefore, the estimate of 100 m^/s will be adopted for Field Trip 1 data. From the flood hydrographs, the volume of flow passing the site whilst this base flow rate was exceeded is given in Table 5.4.

Flood April 1988 July 1988 Total Duration (h) 32.4 16.8 49.2 Volume (Ml) 18720 14150 32870

Table 5.4 Duration and Volume above Threshold of Motion - Numeralla River - Trip 1- The flow volume of 32870 Ml and the corresponding distance moved of 45 metres would then become the first point in the distance moved v flow volume relationship for the site. More data must be gathered before any quantifiable relationship can be established. 5.3.2 Field Trip 2 - Julv 1989 As discussed in Section 5.2, while numerous floods occurred between Trips 1 and 2, most were insufficient to commence the movement of the bed material. This is evidenced by the short distance moved by the tracers - average distance of 12 metres, range 0 to 7 6 metres. Examination of Table 5.1 confirms this assumption in conjunction with the estimate of the threshold of motion from Field Trip 1 data. Only the floods of November 1988 and late April 1989 reached peak flow rates above 100 m^/s. This suggests that the threshold value estimated previously of 100 m^/s is probably of the right order. As the flood of late April 1989 only just exceeded this flow rate, any contribution would have been minor. Therefore, the volume of flow passing the site with flow rate greater than 100 m^/s during the November 1988 flood of 4082 Ml will be adopted as having caused the movement. 71

Tables 5.5 and 5.6 detail the location of the tracers found for each series, and highlights the lack of movement overall.

This data yields the second point in the relationship between distance moved and flow volume. The results to date have a flow of 3287 0 Ml causing a movement downstream of 45 metres (Field Trip 1) and a flow of 4082 Ml resulting in only 12 metres movement (Field Trip 2).

Table 5.5 Numeralla River - Series 1 Tracers - Located July 1989.

Chain Particles Distance Distance Moved No. Located Moved Since Between Trips Placement (m) 1 & 2 (m)

1 235 6 NF 0

3 398 10 4 4 321 8 1 5 313 274 359 10 8 161 1 2 153 308 373 1 0 1 0 6 363 80 0 407 0 NF 245 0 0 7 393 0 0 137 1 1 8 343 278 335 15 0 0 15 0 0

9 355 297 371 345 0 20 0 0 0 20 0 0 10 282 310 337 272 28 28 76 85 28 3 0 1 362 280 214 360 71 132 11 394 306 380 347 40 33 253 125 40 8 NF 1 395 369 262 346 72 63 133 294 0 1 2 106 12 256 341 300 258 396 46 62 14 401 43 1 12 1 NF 0 342 44 0 13 266 377 331 273 44 395 47 7 1 196 NF NF 298 334 366 5 14 156 0 0 68 14 292 271 351 358 247 0 3 17 90 35 0 0 1 3 25 301 296 14 7 0 0 15 270 324 241 361 3 0 8 7 NF NF 0 0 299 3 0

Note: NF denotes particles not found in the particular field trip. 72

Table 5.6 Numeralla River - Series 2 Tracers - Located July 1989.

Chain No. Particles Located Distance Moved Since Placement (m)

1 79 131 43 133 0 3 2 8 148 1 2 118 22 106 136 134 10 9 0 0 0 144 39 142 49 0 0 0 10 3 62 112 122 4 5 8 10 0 129 68 1 12 4 127 120 150 24 0 0 0 0 56 0 5 107 37 29 1 36 8 72 0 6 130 0 6 92 0 5 7 48 27 3 0 5 4 8 105 45 7 0 143 8 9 121 44 89 6 34 0 34 104 50 2 10 138 71 81 2 20 0 145 139 80 25 3 3 11 25 83 149 111 57 41 2 0 50 76 12 18 77 35 0 13 113 147 96 7 0 0 117 115 140 13 8 0 14 38 0 132 65 91 20 0 0 0 42 15 110 125 141 41 0 0 0 0 93 103 0 0 73

^ CONCLUSIONS 6-1 General This report has described the principles underlying, and the preliminary stages of the implementation of, a program for monitoring bed load discharge in NSW rivers. The program has been initiated by the Department of Water Resources, with the object of developing strategies which will permit the extraction from a river of commercially valuable sand and gravel, without detriment to the environment of the river.

It has become evident, in the course of the project, that the complete implementation of the program will be a prolonged and expensive operation. The field operations have been hampered by many of the practical difficulties which arise in such undertakings. Consequently, and particularly in view of the financial constraints operating throughout the period of the project, it has not been possible to reach firm conclusions concerning the relationship between bed load discharge and streamflow parameters. However, as described in the report, valuable experience concerning the practical aspects of the program has been gained, and some tentative examinations of the relationships between bed load discharge and streamflow parameters have been possible.

The experience gained in the course of the project has made possible the formulation of a series of recommendations and guidelines which are expected to be of value in the further development of the monitoring program.

6.2 Recommendations for Further Development Listed below is an itemised account of the recommendations made throughout the report. They are provided to improve the data collection techniques and to ensure the availability of all the necessary data for subsequent analysis. i) As evidenced by the Wilson River site, a monitoring site should be initially selected on a reach of river that, in the medium term at least, has some degree of stability.

The reach of river under consideration must be investigated with respect to the history of channel relocation. Active reaches should be avoided to ensure that the site established will continue to provide an adequate model of the total movement of material throughout this section of the river system. ii) Locating the transect after a flood event can be made easier by establishing a permanent bench mark on the actual line of the transect. Then, for each future trip this bench mark can be used as the reference point so that the results of all trips can be easily compared. 74 iii) The results to date indicate that little correlation exists between the distance moved by a tracer and the grain size of the tracer itself. To further test this, it is recommended that the weight of each tracer be recorded in future.

It may be established that the size distribution of the tracers used is not significant, as it appears that other factors influence the degree of activity of the tracers. Location in the river channel of vegetation cover has been highlighted as a major factor at all the sites. The extent of intermixing of the tracers with the natural material influences distance moved as evidenced by the longer distance moved by a new series of tracers placed on the surface compared to a previous series mixed by past floodwaters. iv) Crucial to the determination of the volume of bed load material moved is the data supplied by the scour chains.

The success rate of recovery of the tracers has provided, in most cases, an adequate measure of the distance moved. The width of activation can be easily measured by cross sectional surveys. From experience however, the depth of activation as recorded by the scour chains is the most vulnerable component.

As discussed in Section 2.3.4, the method of installing the scour chains has undergone considerable development. Experience shows that the best method of placement is site specific. A method which works for one site is unsuitable for another. It would therefore appear that the actual size matrix of the bed material is the controlling factor.

Fine grained or sandy sites have proven unsuitable for the star picket method. Resistance to movement at these sites is not sufficient without some form of anchoring. On the other hand, very coarse grained sites inhibit the initial driving of the steel picket and make removal even more difficult.

Therefore, to ensure the permanence of the scour chains in areas which have been highlighted as unsuitable for one type of method, it is recommended that a form of anchoring be used in all cases. If bed rock is in close proximity, bolting of the chain should be considered. In sandy sites, the placement of a concrete pad either on the bed rock or as an anchor should be implemented.

The expenditure of significant effort in securing satisfactory and permanent anchorage of the scour chains is fully justified, as the data yielded by the chains is vital to the overall success of the program. 75

V) The adoption of the procedure for surveying the elbow of the chain once located and the natural surface when reset (as described in the report) is suggested. This will remove the subjectivity of measuring the length of chain.

Implementation requires carefully designed and practical field sheets. The suggested formats are shown in Appendix A. vi) The detectors used have difficulty in locating the scour chains after a flood event, especially if a large amount of fill has occurred.

As the magnets used with the tracers give out a strong signal, it is suggested that several magnets be glued to the chains to assist in future recovery. vii) When an unidentified tracer is located, it has been found that use of the scatter diagram constructed by measurement of the principal axes of a rock is time consuming and does not lead conclusively to identification.

The use of the ROCKID program is recommended as it employs a consistent and unsubjective means of identifying a rock. viii) The current method of determining the distance moved for each particle involves tedious and repetitive calculations. The co-ordinate system imposed by the Total Survey Station system is over accurate and requires manipulation by hand to convert to a distance in a downstream direction.

Alternative methods should be investigated to reduce the time required for analysis. One method would be to set up a grid system at the site based on the streamline distance downstream. It has been found that the critical component is the location of a tracer in the downstream direction and not its exact location across the channel. Therefore, pegs can be set out identifying distances of 50, 100, 150 metres etc., along the reach from the transect. When resetting a site, strings could be placed across the channel and on locating a tracer, a tape measure could be used to determine the distance moved, which can then be duly recorded.

Another method would be to establish the locations of the 50, 100 and 150 metres "contours" etc. of distance travelled. The co-ordinates of these contours could then be determined. A computer program could then determine the distance moved by a tracer by input of the co-ordinates of the tracer as determined by stadia survey. The latter method has the advantages of speed and allows easy plotting of the data by the computer. 76 ix) As refinement of the results proceeds, it will become desirable to have an accurate measure of the porosity of the natural bed material.

To date no detailed field measurements of this parameter have been undertaken and all calculations presented in this report have used an adopted value of 0.3.

It will be desirable to establish the porosity of the material at each site and to regularly monitor the site to check its validity over time and differing conditions.

X) The three sites presented in this report were chosen, amongst other reasons, because of the availability of up to date streamflow records. Lack of this vital information prevented analysis of other sites in the program.

To ensure the availability of the streamflow data once a monitoring site has been reset, the gauging station applicable should have its records removed, analysed and archived on a more regular basis than the current twelve months practice, normally adopted by the DWR. xi) As mentioned previously the activity of a tracer appears to be influenced by the degree of intermixing with the bed material. As evidenced in the Never Never River site, tracers placed on the surface move further than other particles from previous series. "Loose" particles may not adequately model the movement of the bed material.

Either more particles should be buried, when initially placed, or the initial movements of a series should be disregarded until mixing occurs. xii) The flow passing a site should be satisfactorily represented by the gauging station chosen.

As discussed previously, the present locations of the gauging stations used for the Never Never River site and the Numeralla River are inappropriate as major tributaries enter between the monitoring site and the station. Investigation of the other sites also needs to be undertaken. It may be found that installation of a monitoring system consisting of a velocity sensor and logger is required to ensure that flows passing the site are adequately recorded.

The collection of the streamflow data would then be added to the tasks on resetting a site and this would ensure that all necessary data is collected at the one time. An estimate of the cost of this type of system is some $3000.00. Whilst initially expensive, the cost is minor in comparison to remedial works necessary to repair channel bank degradation. 77

Fmrther Analysis As shown in the analysis of the collected data, the identification of the threshold of motion is crucial to the calculations of bed load discharge and in the determination of the relationship between bed load movement and flow volume.

In this project, this threshold value has been estimated by examining the flood hydrograph which caused the bed load movement. The relationship between the flow rate and the duration this flow rate is exceeded appears to indicate changes in the flow regime.

In the case of the Numeralla River, the threshold value estimated in this way tends to be confirmed by the results of Trip 2. However, data is very limited at this time and further investigation is required.

The actual method used assumes that movement occurs once a particular velocity is exceeded, and conversely, stops once the velocity falls below this value.

However, the actual behaviour maybe more complex: it is possible, for example, that movement of the bed begins when the threshold velocity is exceeded but that movement still can continue even after the velocity falls below this value on recession, until a lower limit is passed causing a gradual stoppage of movement. This would involve the inclusion of a greater volume of flow causing the movement than that assumed in the calculations presented in this report.

Another factor influencing the onset of movement is vegetation cover. All sites have highlighted the influence of stability afforded to a gravel bar by vegetation. Depending on the extent and density of this vegetation, the threshold value may in fact not be directly related to the grain size of the material, its weight or matrix composition and may in fact vary from time to time. For example, as shown in the Never Never River, it appears movement of the material did not commence until a flow rate of 100 m^/s was exceeded in the early April 1989 flood. However, in the flood immediately after, a flow rate of only 40 m^/s appears to have initiated movement. This would be explained by the presence of a vegetation cover at the site for the first event. However, scouring in the first event would have removed the vegetation, allowing easier movement by the second event. Further studies in the estimation of this threshold of motion are therefore required. These studies will require more data than is presently available. Field observations should also accompany this type of analysis to confirm the validity of the estimated value. 78

In conclusion, the Department of Water Resources has undertaken this research program to help preserve the natural environment without the imposition of unreasonable restrictions on the gravel extraction industry. Approaches to major companies involved in the industry should be made to seek finance to support this costly program. The availability of adequate support will help improve the coverage throughout the State and increase the ability to more accurately determine the natural rate of supply of sand and gravel by the State's rivers. 79

REFERKNCKS

Coates, B.P., Outhet, D.N., & Roberts, K.T. "Measurements of Bed Material Discharge in Rivers of N.S.W." Australian and New Zealand Geomorphology Group 4th Conference, Buchan, Victoria, Feb 1989.

Hassan, M.A.,Schick A.P. and Laronne J.B. " The Recovery of Flood Dispersed Coarse Sediment Particles - a Three Dimensional Magnetic Tracing Method." CATENA, Suppl Bd. 5 1984, pp 153-162.

Hean, D.S. & Nanson G.C. " Serious Problems in Using Equations to Estimate Bedload Yields for Coastal Rivers in N.S.W." Australian Geographer,18, 1987, pp 114-123.

Kellerhals,R. & Bray D.I. "Sampling Procedures For Coarse Fluvial Sediments " ASCE JHydDiv HY8 1971, pp 1165 - 1180.

Terzaghi, K. & Peck, R.B. "Soil Mechanics in Engineering Practice" Wiley & Sons 2nd Edition, 1967.

Laronne,J.B. "Recommended Sites For Measuring Bed Material Discharge in N.S.W. Rivers " Report to N.S.W. Department of Water Resources, 1987.

Laronne, J.B. "Recommended Bed Material Discharge Measurement Techniques for N.S.W. Rivers" Report to N.S.W. Department of Water Resources, 1987.

Bagnold, R.A. "Bed Load Transport by Natural Rivers" Water Resources Research, Vol 13, No. 2, April 1977.

Department of Water Resources "Water Resources of the Hastings River Valley" Report No. 6, October 1967.

Department of Water Resources "Water Resources of the Bellinger River Valley" Report No. 12, October 1969.

Department of Water Resources "Water Resources of the Murrumbidgee River Valley" Report No. 15, November 1972. 80

APPRWnTY A - FIELD SHEETS pAGE

A1. Tracer Measurement 81

A2. Tracer Location 81

A3. Scour Chain Exposure 82

A4. Tracer Recovery 83 81

APPENnrx n - FTRT.n SHEETS The following sections provide an example of each field sheet recommended for use in the set-up and subsequent resetting of a monitoring site. ALs Tracer Measuremg^nt: To assist in the identification of a tracer upon recovery if its number is missing or illegible, the principal axes of the rock (as shown in Figure 2.3) should be measured and tabled before placement.

Table A.l provides the a, b and c axis measurements for a portion of the Series 1 tracers on the Never Never River. The field sheet shown includes the weight of each particle, although this measurement was not taken for this particular series of tracers.

Table A.l Tracer Measurement Sheet Tracer Measurement Site: Never Never Series: 1 Colour: Pink Rock A B C Wt Rock A B C Wt 1 35 29 23 11 46 33 25 2 42 35 25 12 42 41 30 3 47 34 19 13 50 36 24 4 38 37 27 14 44 32 22 5 42 29 16 15 38 31 26 6 50 31 25 16 38 38 18 7 48 33 22 17 49 37 19 8 39 31 23 18 41 36 24 9 44 29 20 19 44 33 22 10 41 26 18 20 37 35 23

A2 • Tracer iKPcation On placement of a series of tracers, the location of each rock should be recorded on a field sheet. An example of this sheet is presented in Table A.2 using the Never Never River Series 1 tracers as an example. 82

Table A.2 Tracer Location Sheet

Site: Never Never River Series: 1 Colour: Pink Chain Particle Numbers Comments No.

1 88 121 47 127 28 Water Edge 30 72 26 3 19 138 130 2 135 76 113 96 15 24 59 70 116 10 103 62 3 46 12 73 71 120 84 25 36 119 109 64 107 4 99 136 6 85 31 87 39 117 61 79 89 11 5 134 118 4 1 115 97 95 110 53 50 45 124 6 17 41 93 14 2 35 20 94 126 23 52 66 7 40 104 101 65 63 133 43 74 131 108 56 57 8 48 75 58 60 37 111 7 67 27 86 68 44 9 49 80 5 123 69 9 16 78 100 128 125 38 10 98 92 22 8 21 Water Edge 18 139 77 81 129 54 11 132 51 42 33 112 12 90 32 105 91 114 13 137 29 13 83 34 14 102 122 106 82 55 hl^ Scour Chain Exposure Although it has previously been concluded that the survey method of measuring the amount of scour and fill should be used, on locating the chain it is still important to have some method of checking at what level the elbow is expected to be located. When the chains are installed or reset, the length of exposure should be noted. After a flood event, it has been found that location of the elbow of a scour chain is difficult, especially if located within or near the low flood channel. A note therefore, should be made of the length from the end of the chain to the elbow and this compared with the length marked as original exposure, to ensure the former is not less than the latter. If so, the true elbow has not been found and further digging is required. 83

Table A. 3 shows an example of the field sheet recommended for this purpose. A complete record of exposure details can then be kept for each field trip.

Table A.3 Scour Chain Details Sheet

Site: Never Never River Trip: Date: May 1988 Chain Original Exp. Scour Reset Exp. Comments No. (End to Old (End to (End to N.S.) (mm) Elbow) New N.S.) (mm) (mm) 1 310 300 210 2 170 110 40 3 520 620 200 Reset 4 220 310 70 5 460 385 260 6 180 280 150 7 210 230 130 8 240 210 180 9 200 260 180 10 370 300 250 11 210 280 190 12 130 Lost 140 New chain 13 170 210 160 14 160 130 130

Note, that if this recommended method was employed previously, errors such as those in chains 1,2,5,8,10 and 14 would not have occurred. In these cases, the true elbow was not found as the suggested length to the elbow was actually less than the original exposure. This would mean that the chain somehow remained vertical whilst fill occurred, which of course is impossible. This highlights the difficulty in locating the elbow and only care and persistence can ensure the correct location of the elbow.

M.S Tracer Recovery On recovery of a tracer, its position should be marked to enable later survey.

Table A.4 gives an example of the field sheet to be used to illustrate the information necessary for marking a tracer's location. Note also, if the number of the recovered tracer has worn off or is partially illegible the a, h^^^tìà^^aKes should be measured and noted on this sheet. ^^^^ " 84

Table A.4 Tracer Recovery Sheet

Site: Never Never River Trip: 3 Date: May 1989

Stake Colour Rock Depth Stake Colour Rock Depth No. No. (mm) No. No. (mm) 141 0 37 180 115 0 140 100 141 Y 2 200 27 Y A 52 50 141 Chain 13 — B 38 39 Chain 14 - C 17 133 0 35 180 73 Y 25 0 41 Chain 12 - 152 0 A 52 112 Y 67 50 B 42 99 P 89 150 C 28 150 135 0 42 180 160 P 19 50 132 Chain 11 - 52 P 54 250 147 0 112 200 17 P 95 0 127 0 A 94 200 23 0 10 0 B 61 87 P 121 40 C 34 29 Y 21 100 62 Y 17 50 51 Y 101 200 54 P 27 100 82 Y 116 150 54 P 12 50 94 Y 27 50 85

APPENDIX B - PROGRAMS PAGE

Bl. Rock Identification Program 86

B2. Reduction Program 88

B3. Cross Section Reduction Program 90

B4. Transect Plot Program 92

B5. Rate Program 97 86

APPENDTX B - PROGRAMS

This section gives a brief description of each program written by the author in the course of this project. Included is a listing of the source code, together with the data requirements, a sample session and an example or reference to the output. A brief discussion of the survey reduction program and a sample session is included, although this program was written by a consultant and therefore no program listing is given in this report.

BTs Rock Identification Program In establishing the bed load monitoring program. Dr. Laronne recommended that for each of the tracers used, the principal axes of the rock should be measured. This was to assist in the identification of the rock should its number be worn off during movement by a flood event. With these measurements, he suggested a scatter diagram be drawn, showing the variation of grain size (b-axis) with both elongation (a-axis) and thickness (c-axis). Practical experience has shown that the measurement of the rock axes can be very subjective or simply in error, and subsequent use of the scatter diagram does not lead conclusively to the identity of the tracer. To improve the manner of rock identification, use of a program called ROCKID is recommended. This program uses as input the data base of a, b and c axis measurements for each tracer in a single series for comparison with the rock required to be identified. It sums the difference between the a, b and c axes of the subject rock with each rock in the series, then presents the five closest alternatives to the user. From this list (or more if required) the identity of the rock can be successively narrowed until the best possible choice remains, taking into account both size and numbers previously identified. A listing of the program is given in Table B.l, and the data requirements and a sample session are given below. The program is used interactively after the input of the data base, that is, the a, b and c axis measurements for the particular series under examination. Note, the total number of tracers must be included as the first line in the data base. For example, we will attempt to identify a tracer from Series 1 of the Never Never River, measured in the field as 64, 48 and 40 mm for a, b and c axes respectively: 87

Sample Session: ROCKID

ROCK IDENTIFICATION PROGRAM

Enter name of data file? SERIESl.ID Enter rock to be identified? 64,48,40

Job Executing • • • Please wait

Rock A B C DEL 89 65 48 41 2 80 58 47 41 8 87 57 49 40 8 88 64 49 32 9 119 64 53 34 11 Print more? n Identify another rock? n

JOB COMPLETED

The above example indicates that rock number 89 is the closest in size to the subject rock, and would be adopted as the subject tracer. Table B.l ROCKID Program Listing

10 ' BED LOAD PROJECT 20 ' Rock identification prograi 30 ' ftir unnumbered rocks 40 ' A.J. McCabe No v 1989 50 Oltl A(500),B(500),C(500),RANK(500),OELT(500),Rf1AX(500] 60 DIM AR(500),BR(500),CR(500) 70 PRINT "ROCK IDENTIFICATION PROGRAfI' 80 PRINT:INPUT "Enter name of data file "iFINAMEi 90 OPEN FINAMEJ FOR INPUT AS tl 100 INPUT II, NROCK 110 FOR 1=1 TO NROCK 120 INPUT S1,A{I],B(I),C(I) 130 NEXT I U0 PRINT-.INPUT "Enter rock to be identified '-.AljBl.Cl 150 PRINT:PRINT "Job Executing Pleas e Waif 160 FOR 1=1 TO NROCK 178 IF A1=0 THEN OELT(I)=ABS(B(I)-Bl)+ABS(C(I)-Cl):GOTO 210 180 IF B1=0 THEN DELT(I)=ABS(A(I)-Al)+ABS(C(I)-Cl):GOTO 210 190 IF C1=0 THEN 0ELT{I)=ABS(A(I)-A1)4ABS(B(I)-B1):60T0 210 200 0ELT(I)=ABS(A{I)-A1)+A6S(B(I)-B1)+ABS(C{I)-C1) 210 NEXT I 220 FOR 1=1 TO NROCK 230 RnAX(I)=0 240 NEXT I 250 FOR J=NROCK TO 1 STEP -1 260 FOR 1=1 TO NROCK , 270 I F DELT(I)>=Rf1AX(J) THEN RnAX(J)=DELT(l):L=I 280 NEXT I 290 DELT(L)=-1 300 RANK(J)=L:AR(J)=A(L):BR(J)=B(L):CR(J)=C(L ) 310 NEXT J 320 L0U=1:HIGH=5 8 8 330 PRINT:PRINT "ROCK '¡TABÌie) •A';TAB(20) •B';TAB(30) •C';TAB(40) "DEL " 340 PRINT:IF LOW)NROCK THEN GOSUB 460 350 FOR I=LOW TO HIGH 360 I F DNROCK THEN GOSUB 460:6OTO 350 370 PRIN T RANK(I);.-PRINT TAB(8) AR(I];:PRINT TAB(18) BR(I); 380 PRIN T TAB(28) CR(I);:PRINT TAB(40) Rt1AX(l] 390 NEXT I 400 PRINT CHR$(7):PRINT:INPUT 'Print more ' 410 IF A$='y' OR A$="Y" THEN L0W=L0W+5:HI6H=HIGH+5:60T0 340 420 PRINT:INPUT "Identify another rock •;Q2$ 430 IF Q2$="y* OR 02$='Y" THEN GOTO 140 440 CLS:PRINT 'JOB COMPLETED' 450 END 460 ' list again subroutine 470 PRINT:INPUT 'Ali rocks are listed ... List again ";03i 480 IF 03$="y" OR 03$="Y" THEN GOTO 500 490 GOTO 420 500 L0W=1:HIGH=5 510 PRINT:PRINT 'ROCK •;TAB(10) •A';TAB(20) 'B';TAB(30) •C';TAB(40) "DEL ':PRINT 520 RETURN

Reduction Program

The reduction of the basic survey data of slope distance, deflection angle, bearing and rod height from the Total Survey Station is achieved by use of a program called REDUCTN. This converts the survey data to a X-Y co- ordinate system and a reduced level based on the location of the instrument to a known .bench mark.

It was written by Mr. Brian Franklin and is part of a suite of programs which allow downloading of the suirvey data from the survey equipment's memory modules onto a personal computer.

The detail provided below is more for the information of DWR field staff than for information relating to the entire bed load program.

Downloading of the field data onto a personal computer results in two copies of the data, with filename extensions of .OBS and .WRK. The former is for backup purposes and should not be edited at any stage. The latter is the "work" file where any modifications regarding comments or corrections to bearings should take place.

The .WRK file is used as input data for the REDUCTN program. Output from the program is to the printer as well as to an .ASC file which lists the reduced data in sequential order. Note, this file is used by the XSECT program for extraction of cross sectional data.

On execution of the program, the user is requested for the name of the data file. The .WRK extension is default for the program. Interactively the user is requested for the co-ordinates and reduced level of each instrument set-up. Once the first set-up point is entered, the program 89 calculates all further points until the next instrument set-up. The foresight to this point allows calculation of its co-ordinates by the program, and these can then be entered by the user at the prompt to continue execution.

A sample session is provided below with a sample of the input and output produced given in Table B.2.

Sample Session: REDUCTN

*** REDUCTION OF TOPO DATA ***

PRINTER MUST BE CONNECTED AND TURNED ON

1. Reduce and Printout Reductions 2. Exit to DOS.

Input number and Press Enter? 1 Input Filename (NO EXTENSION)? NEVER12

*** STATION DETAILS ***

Station Number Height of instrument East Co-ord of Station North Co-ord of Station Height of Station

Y/N ... (Y)? Y Table B.2 REDUCTN Program - Sample Input and Output

HNEVER12 C/S ME 10.2.88 ELMS ASSUMED SBM2 1.522BM1180.00 052 0134 .861089 .4210179 .58301 .6 BMl BMl BACK SIGHT 053 0.0 90 .00 300 .00 1 .522BM2 055 0005 .232086 .4025285 .20452 .1 N/S TOP BANK R/B 056 0008 .611093 .1445285 .54352 .1 N/S SLOPE 057 0014 .053102 .1825286 .59203 .1 BED BOT BANK R/B 058 0020 .748098 .3620285 .33453 .1 BED 059 0035 .968094 .3920284 .23353 .1 BED BOT BANK L/B 060 0037 .034093 .0850283 .54053 .1 N/S SLOPE 061 0040 .262094 .2035285 .09452 .1 N/S BOT HIGH BANK 062 0046 .822088 .2500282 .28051 .1 N/S TOP HIGH BANK 063 0134 .877089 .4325179 .59301 .6 BMl

Job Number NEVER12 C/S Surveyor ME Date of Survey.. 10.2.8

Station Number BM2 East Co-ord of Station.... 1000 North Co-ord of Station..1134.9 Height of Station..99.40 90

EAST NORTH LEVEL CODE REMARKS 1000.058 1000 .04 100.021 BMl BMl BACK SIG 1000 1134 .9 99.4 BM2 994.963 1136 .282 99.125 N/S TOP BANK R/B 991.732 1137 .256 98.334 N/S SLOPE 986.869 1138 .911 94.826 BED BOT BANK R/B 980.237 1140 .403 94.717 BED 965.275 1143 .811 94.902 BED BOT BANK L/B 964.104 1143 .784 95.788 N/S SLOPE 961.251 1145 .4 95.773 N/S BOT HIGH BAN 954.299 1145 .004 101.115 N/S TOP HIGH BAN 1000.019 1000 .024 99.972 BMl

Cross Section Reduction Program

This program uses the co-ordinates from the REDUCTN program to determine the chainage of a cross section in relation to a user defined starting point. A listing is given in Table B.3.

It allows analysis of the actual transect before, during and after a flood event, and reguires input of an edited version of the .ASC file from the REDUCTN program. The .ASC file contains all the points in a suorvey of a cross section, including all intermediate points in moving from the known bench mark to the start of the cross section, and closing back to the bench mark. Therefore, the data file must be edited so that the file contains only the cross section information. After editing, to preserve the original .ASC file, the new file should be renamed with a .XSI extension.

Using this new file, the program is then executed to determine chaînages for the cross section. The sample session below illustrates its use and capabilities. Output is given in two forms. It can be sent to the printer in the form shown in Table B.4. Alternatively the data can be stored in a file with extension .XSO which is then used by the TRANS and RATE programs. Sample Session: XSECT

CROSS SECTION REDUCTION PROGRAM

Enter name of input file (no element .XSI)? NEVER12 Enter from which bank readings start? R Enter chainage of first point? 0 Print output file or save for TRANS program (p/t)? P 91

Job Completed Continue or Quit? Q Table B.3 Listing of XSECT Program

10 ' BED LOAD PROJECT 20 ' Cross section reduction program 30 ' A.J.dcCabe Nov 1989 40 DIM E{300), N(300), RL(300), T$(300), CH(300), EAST(300), NORTH(300), LEVEL(300], TEXT$(300) 50 CLS : PRINT 'CROSS SECTION REDUCTION PROGRAM' 60 PRINT : INPUT "Enter name of input file (no element .xsi) '; FINAHE$ 70 Fl$ = FINAMEÎ + '.xsi' 80 OPEN Fl$ FOR INPUT AS «1 90 t1 = 1 100 IF EOFd) THEN « = H - 1: GOTO 130 110 INPUT «1, E(M], N(M), RL(ri], T$(M] 120 t1 = M + 1: GOTO 100 130 CLOSE m U0 PRINT : INPUT 'Enter from which bank readings start '; 0$ 150 IF 0$ = '!' OR 0$ = "L' GOTO 280 160 IF 0$ = 'r' OR 0$ = "R* GOTO 180 170 GOTO 140 180 ' right bank reversing 190 K = 0 200 FOR I = f1 TO 1 STEP -1 210 K = K + 1 220 EAST(I) = E(K) 230 NORTH(I) = N{K) 240 LEVEL(I) = RL(K) 250 TEXT$(I) = T$(K) 260 NEXT I 270 GOTO 350 280 ' left bank renaning 290 FOR I = 1 TO II 300 EAST(I) = Ed) 310 NORTH(I) = N(I) 320 LEVEL(I) = RL(I] 330 TEXT${I) = Ti(I) 340 NEXT I 350 ' chainage calcs 360 PRINT : INPUT 'Enter chainage of first point '; CH(l) 370 FOR I = 2 TO H 380 DELO = SOR((EAST(I) - EAST{I - D) ' 2 + (NORTH(I) - NORTH(I - D) ' 2) 390 CH{I) = CH(I - 1) + DELD 400 NEXT I 410 ' print of results 420 PRINT 430 INPUT 'Print output file or save for TRANS program (p/t) ';025 440 IF 02$='t' OR Q2$='T' THEN F2$ = FINAflES + '.xso': GOSUB 660 : GOTO 470 450 IF 02$='p' OR 02$='P' THEN GOSUB 540:6OTO 470 460 GOTO 430 470 CLS : PRINT 'Job Conpleted" ' 480 IF 02$='t' OR 02$='T' THEN PRINT 'Output placed in file ..'; F2$ 490 CLOSE «1 500 PRINT : INPUT 'Continue or Quit'; 01$ 92 510 IF 01$ = 'e' OR 01$ = "C" THEN GOTO 50 520 IF 01$ = "O" OR 01$ = "q* THEN END 530 GOTO 500 540 ' output file print subroutine 550 LPRINT F2$ 560 LPRINT • ' 570 LPRINT : LPRINT TAB(10); "Chainage'; : LPRINT TAB(30); "Reduced Level"; : LPRINT TAB(50); "Comments" 580 LPRINT " ' 590 FOR I = 1 TO t1 600 LPRIN T TAB(10); USING "#«1«.*«"; CH(I); 610 LPRIN T TAB(35); USING "jt#«.ftjlll"; LEVEL(I); 620 LPRIN T TAB(50); TEXT$(I) 630 NEXT I 640 LPRINT : LPRINT " 650 RETURN 660 ' output for trans program 670 OPEN F2$ FOR OUTPUT AS «1 680 PRINT #1, F2$ 690 FOR I = 1 TO M 700 PRIN T «1,USING "W«.»«"; CH(I); 710 PRIN T 111," "; 720 PRIN T «1,USING "tlt«.8«1t"; LEVEL(I); 730 PRIN T #1," "; 740 PRIN T «1,TEXT$(I) 750 NEXT I 760 RETURN

Table B.4 Sample Output from XSECT Program Chainage Reduced Level Comments 0.00 101.116 N/S TOP HIGH BANK 6.96 95.774 N/S TOP HIGH BANK 10.24 95.789 N/S SLOPE 11.41 94.903 BED BOT BANK L/B 26.76 94.718 BED 33.56 94.827 BED BANK R/B 38.69 98.335 N/S SLOPE 42.07 99.126 N/S TOP BANK R/B

B4. Transect Plot Program The TRANS program is used to plot the movement of the transect or any other cross section during different stages of a flood event. Data requirements are a modified form of the data file produced by the XSECT program as shown below in Table B.5. Table B.5 - Data Entry Requirements for TRANS Program 1 Title of Job eg. WILSON RIVER . 2 Cross Section Title eg. BEFORE 3 No. of Points 4 Chainage, Elevation, Comments for each point 5 Cross Section Title eg. DURING 6 No. of Points 7 Chainage, Elevation, Comments for each point 93

8 Cross Section Title eg. AFTER 9 No. of Points 10 Chaînage, Elevation, Comments for each point.

The data file produced by the XSECT program contains the cross section title, and chaînage, elevation and comment for each point of a cross section. If we wish to examine the change in cross section through the flood event, the scour/fill data gives the before, during and after information. This would involve three data files each identified by the .XSO extension. These should then be combined to one data file, called say TRIPl.XSO and any missing data requirements such as Job Title and the number of points in each cross section should be added.

The program can then be executed as per the sample session provided below. An example of the output is shown as Figure 3.5 for the Wilson River after the first field trip A listing of the program is provided in Table B.6.

Sample Session: TRANS

BEDLOAD PLOT PROGRAM

Enter name of data input file? TRIPl.XSO Enter no. of cross sections (max 10)? 3 Specify scale (y/n)? n

PLOT OF CROSS SECTIONS Before proceeding ensure plotter is turned on, 4 pens are located in pen holders no. 1,2,3 and 4 and paper (A4) is in position. Strike any key when ready ....

JOB COMPLETED Continue, Reprint or Quit? Q

Note, the scale of the plot can be specified by the user if for example a standard scale for all sites is required. The user simply enters the minimum and maximum values for the X and y axes and the number of divisions on each axis.

Table B.6 TRANS Program Listing

10 ' BED LOAD PROJECT. 20 ' Trans prograa 30 ' A.J. fIcCabe Nov 1989 40 OEFINT N,I,f1,K,J 50 DIM P(10.100,2),T$(10,100),XN(50),YN(50),Y$(50),n(100).TEX$(l0) 60 CLS 70 PRINT "BED LOAD PLOT PROGRAfi' 80 INPUT "Enter na»e of data input file" ;FINAf1E$ 90 OPEN FINAMES FOR I«PUT AS II 100 INPUT 'Enter no. of cross sections (max 10) "jN 110 INPUT «1,TIT$ 120 FOR 1=1 TO N 130 INPUT «1,TEX$(I) 94

U0 INPU T II,fid) 150 FO R J=1 TO M(I] 160 FO R K=1 TO 2 170 INPU T ll,P(I,J,K) 180 NEX T K 190 INPU T «1,T$(I,J] 200 NEX T J 210 NEXT I 220 CLOSE ttl 230 INPUT "Specify scale (y/n) ^ZJ 240 IF Z$="yes" OR Z$='YES* OR Z$='y" OR Z$='Y' THEN 60SUB 2000:GOTO 270 250 IF Z$="no" OR Z$='NO" OR Z$="n" OR Z$="N' THEN GOTO 270 260 GOTO 230 270 CLS 280 PRINT "PLOT OF CROSS SECTIONS' 290 PRINT 'Before proceeding ensure plotter is turned on," 300 PRINT '4 pens are located in pen holders no. 1,2,3 and 4' 310 PRINT 'and paper is in position.' 320 IF Z$='yes" OR ZJ='YES' OR Z$='Y' OR ZJ='y" THEN GOTO 790 330 i1INY=P(l,l,2) 340 FOR 1=1 TO N 350 FO R J=1 TO nil] 360 I F P(I,J,2) <= MINY THEN f1INY=P(I,J,2) 370 NEX T J 380 NEXT I 390 hAXY=P(1,1,2) 400 FOR 1=1 TO N 410 FO R J=1 TO 11(1) 420 I F P(I,J,2) ) HAXY THEN nAXY=P(l,J,2) 430 NEX T J 440 NEXT I 450 mNX=P(l,l,l) 460 IF N=1 GOTO 500 470 FOR 1=2 TO N 480 I F P(I,1,1) <= MINX THEN !1INX=P(1,1,l) 490 NEXT I 500 HAXX=P(l,ri(l),l) 510 IF N=1 GOTO 550 520 FOR 1=2 TO N 530 I F P{I,f1(I],l) )= MAXX THEN f1AXX=P(I,fl(I),l] 540 NEXT I 550 ' 560 ' deterraining range of x-axis 570 ' 580 XR=f1AXX-HINX 590 IF XR <= 50 THEN XFACT1=5: GOSUB 1860 :GOTO 690 600 IF XR ) 50 AND XR <= 100 THEN XFACT1=10: GOSUB 1860 : GOTO 690 610 IF XR ) 100 AND XR <= 200 THEN XFACT1=20: GOSUB 1860: GOTO 690 620 IF XR ) 200 AND XR (= 400 THEN XFACTU40: GOSUB 1860: GOTO 690 630 IF XR ) 400 AND XR <= 800 THEN XFACT1=80: GOSUB 1860 : GOTO 690 640 IF XR ) 800 AND XR (= 1200 THEN XFACT1=100: GOSUB 1860: GOTO 690 650 IF XR ) 1200 AND XR <= 2000 THEN XFACT1=200 : GOSUB 1860 : GOTO 690 660 IF XR ) 8000 THEN XFACT1=1000: GOSUB 1860: GOTO 690 670 IF XR ) 2000 AND XR (= 4000 THEN XFACT1=500: GOSUB 1860: GOTO 690 680 IF XR > 4000 AND XR <= 8000 THEN XFACT1=1000: GOSUB 1860: GOTO 690 95

690 ' 700 ' determining range of y-axis 710 ' 720 YR=MAXY-«INY 730 IF YR <= 1 THEN ELFACT=.2 : GOSUB 1940 : GOTO 790 740 IF YR ) 1 AND YR (=5 THEN ELFACT=.5 : GOSUB 1940 : GOTO 790 750 IF YR > 5 AND YR {= 10 THEN ELFACT=1! : GOSUB 1940 : GOTO 790 760 IF YR )10 AND YR <= 20 THEN ELFACT=2 : GOSUB 1940 : GOTO 790 770 IF YR ) 20 im ELFACTrS ; GOSUB 1940 : GOTO 790 780 ' determining range of plot 790 Xf1IN=X0-XFACT2 800 Xf1AX=Xl+XFACT2 810 YMIN=Y0-ELFACT 820 Yf1AX=Yl+ELFACT 830 ' determining axes variables 840 ' 850 XN(1)=X0 860 NXX=NX+1 870 FOR 1=2 TO NXX 880 XN(I)=XN(I-1)+XFACT2 890 NEXT I 900 YN(1]=Y0 910 NYY=NY+1 920 FOR 1=2 TO NYY 930 YN(I)=YN(M]+ELFACT 940 NEXT I 950 OPEN "duii.dat" FOR OUTPUT AS 12 960 FOR 1=1 TO NYY 970 PRINT «2,USING '*ll«.I";YN(I] 980 NEXT I 990 CLOSE #2 1000 OPEN 'dum.dat' FOR INPUT AS «2 1010 FOR 1=1 TO NYY:INPUT «2,Y$(I):NEXT I 1020 ' 1030 CLOSE «2 1040 ' plotting commands 1050 ' 1: setting user co-ords 1060 IF 01$="r' THEN GOTO 1100 1070 PRINT 'Strike any key when ready ' 1080 B$=INKEY$ : IF B$=*' THEN GOTO 1080 1090 GOTO 1120 1100 PRINT 'Strike any key when ready ' 1110 02i=INKEY$ : IF 02$=" THEN GOTO 1110 1120 OPEN '001111:9600,6,7,l,rs.cs65535,ds,cd' AS 13 1130 PRINT «3,'in;spl;" 1140 PRINT «3,'sc';Xt1IN;XHAX;Yf1IN;Yt1AX 1150 TX=Xf1IN+XFACT2:TY=YI1AX-ELFACT/2 1160 PRINT l3,'pa';TX;TY 1170 PRINT «3,'lb';TIT$;CHRJ(3];'pu;' 1180 ' 2: placing labels on axes 1190 LX=XHIN+(XriAX-Xf1IN)/2-XFACT2/4:LY=YMIN+ELFACT/5 1200 PRINT «3,'pa';LX;LY 1210 PRINT S3,'lb Chainage (m)';CHR$(3);'pu;' 1220 LX=XHIN+XFACT2/4:LY=Yt1IN+(YHAX-Yf1IN)/2 ' 1230 PRINT «3,'pa';LX;LY 1240 PRINT f3,'di0,l;' 1250 PRINT 13,'lb Elevation (•)';CHRJ(3);'pu;' 1260 PRINT «3,'di;' 96

1270 ' 3: draw exes 1280 PRINT «3,"sp2;pa";X0;Y0;'pd;xt;' 1290 XINC=X0 1300 FOR 1=1 TO NX 1310 XINC=XINC+XFACT 2 1320 PRIN T «3,'pa";XINC;Y0;'xt;' 1330 NEXT I 1340 PRINT #3,"pu;" 1350 PRINT l3,"p8";X0;Y0;'pd;yt;' 1360 YINC=Y0 1370 FOR 1=1 TO NY 1380 YINC=YINC+ELFAC T 1390 PRIN T «3,"pa";X0;YINC;'yt;" 1400 NEXT I 1410 PRINT «3,'pu;' 1420 ' 4: placing numbers on axes 1430 XINC=X0 1440 FOR 1=1 TO NXX 1450 PRIN T «3,"pa";XINC;Y0 1460 PRIN T «3,"cp-2,-l;' 1470 PRIN T l3,"ib";XN(I);+CHR$(3] 1480 XINC=XINC+XFACT 2 1490 PRIN T «3,'pu;" 1500 NEXT I 1510 YINC=Y0 1520 FOR 1=1 TO NYY 1530 PRIN T *3,'pa';X0;YINC 1540 YLEN=LEN(YJ(I))+ 1 1550 PRIN T «3,'cp';-YLEN;0 1560 PRIN T «3,'lb";Y$(I);CHR$(3) 1570 YINC=YINC+ELFAC T 1580 PRIN T 13,"pu;" 1590 NEXT I 1600 ' 5: plotting co-ordinates 1610 K0UNT=1:CY=1 1620 PRINT ll3,'sc';Xf1IN;XHAX;YHIN;Yf1AX 1630 FOR 1=1 TO N 1640 PRIN T «3,'sp';KOUNT;"pa';X0;Y0 1650 I F 1)4 AND I<=8 THEN PRINT 13,"115,10;' 1660 I F 1)8 THEN PRINT t3.'lt2,10;' 1670 FO R J=1 TO f1(I] 1680 PRIN T «3,'pa';P(I,J,l);P{I,J,2);'pd;' 1690 NEX T J 1700 PRIN T 13,'pu;' 1710 PRIN T t3,'pa';Xl;Yl 1720 PRIN T «3,'cp';l;-CY 1730 PRIN T l3.'lb';TEX$(I);CHR$(3);'pu;' 1740 K0UNT=K0UNT+1:CY=CY+ 1 1750 I F K0UNT>4 THEN K0UNT=1 1760 NEXT I 1770 PRINT I3,'pu;sp0;' 1780 CLOSE 13 1790 CLS : PRINT 'JOB COHPLETEO' 1800 INPUT "Continue, Reprint or Quit (c/r/q) ';01$ 1810 IF 01$='c' OR Q1$='C' THEN GOTO 60 1820 IF 01J='r' OR Q1$='R' THEN GOTO 1040 1830 IF QiU'q O R 01$='0' THEN GOTO 1850 97

1840 GOTO 1800 1850 KILL "duiti.dat":END 1860 f1AXX=INT{(MAXX+XFACTl)/XFACTl) 1870 HINX=INT(mNX/XFACTl) 1880 X1=HAXX*XFACT1 1890 X0=t1INX*XFACTl 1900 NX=i1AXX-MINX 1910 IF NX {= 5 THEN XFACT2=XFACTl/2 : NX=NX*2 : GOTO 1930 1920 IF NX ) 5 THEN XFACT2=XFACT1 1930 RETURN 1940 f1AXY=INT{(HAXY+ELFACT)/ELFACT) 1950 HINY=INT{(HINY-ELFACT]/ELFACT) 1960 Yl=f1AXY*ELFACT 1970 Y0=«INY*ELFACT 1980 NY=MAXY-MINY 1990 RETURN 2000 ' specify scale subroutine 2010 INPUT "Enter the minimum chainage for the x-axis";X0 2020 INPUT "Enter the «aximum chainage for the x-axis';Xl 2030 INPUT "Enter the minimu« elevation for the y-axis';Y0 2040 INPUT "Enter the maximum elevation for the y-axis";Yl 2050 INPUT "Enter the no. of subdivisions on the x-axis";NX 2060 INPUT "Enter the no. of subdivisions on the y-axis';NY 2070 XFACT2=(X1-X0]/NX 2080 ELFACT=(Y1-Y0)/NY 2090 RETURN

RATE Program This program allows the calculation of the net area of activation for the transect by providing the cross sectional area of the transect under a user-defined stage height. An example calculation is given in Section 4.3.1.

A range of stage heights is entered by the user and the hydraulic properties as shown in the sample session are calculated. To determine the actual area of activation the stage height selected by the user should be chosen so that it is above the level at which any action has taken place, and also at a level that confines the section to the area regularly surveyed.

Note, the program uses the output file produced by the XSECT program for each individual cross section. No modifications are required. A listing of the program is given in Table B.7 . Sample Session: RATE

RATE PROGRAM »

Enter input file (no ext .XSO)? NEVER12 Print to file or screen (f/s)? S Enter start, end and increment? 98,100,0.5 98

NEVER NEVER RIVER - TRANSECT - BEFORE TRIP ONE Stage Ht. Area Perimeter Top Width (m) (sq.m.) (m) (m) 98.0 95.2 48.7 46.9 98.5 119.2 50.8 48.8 99.0 144.0 53.0 50.6 99.5 169.8 55.0 52.3 100.0 196.3 56.5 53.8

Press any key to continue....

CALCULATION FINISHED Continue or Quit (c/g)? Q Table B.7 Listing of RATE Program

10 ' BED LOAD PROJECT 20 ' Rate program 30 ' A.J. HcCabe Nov 1989 40 DIM CH(300), EL(300),T(300) 50 DIH A(300), P(300), T$(300) 60 ' input of data 70 CLS 80 PRINT 'RATE PROGRAM' 90 INPUT 'Enter input file (no ext .xso] "jFINAMEi 100 FU=FINAHE$+'.xso' 110 OPEN Fl$ FOR INPUT AS fl 120 INPUT II,A$ 130 H=1 U0 IF EOF(l) THEN f1=H-l:G0T0 170 150 INPUT «l,CH(H),EL(fl],T$(f1) 160 f1=i1+l:60T0 U0 170 CLOSE II 180 ' calculation of fiiniiuR and taxiiui levels 190 60SUB 380 200 ' print output 210 INPUT "Print to file or screen (f/s) ';0J 220 IF 0$='f' OR 0$='F' THEN OPEN 'rate.out' FOR OUTPUT AS 82: 60SUB 1840: GOTO 250 230 IF 0$='s' OR Q$="S' THEN GOTO 250 240 GOTO 210 250 ' 260 ' specify flood level 270 GOSUB 530 280 IF OJ='f' OR 0$='F' THEN GOTO 310 290 PRINT :PRINT 'Press any key to continue .... ' 300 01$=INKEYJ: IF 01$=" THEN GOTO 300 310 CLS 320 PRINT "CALCULATION FINISHED' 330 IF Q$="f OR 0$='F" THEN PRINT 'Output placed in file : RATE.OUT" 340 INPUT 'Continue or Quit (c/q) ';02$ 350 IF 02$='c' OR 02$='C' THEN GOTO 70 360 IF 02J='q' OR 02$='0' THEN END 370 GOTO 340 380 ' «iniiu« and laxiiui level subroutine 390 ' iiniiui level 400 ' 99

U0 tllNY = EL(1) 420 FOR I = 2 TO M 430 I F EL(I) { HINY THEN MINY = EL(I) 440 NEXT I 450 ' 460 ' maximua level 470 ' 480 MAXY = EL{1) 490 FOR I = 2 TO II 500 I F EL(I] >= MAXY THEN MAXY = EL(I] 510 NEXT I 520 RETURN 530 ' 540 ' calculation of hydraulic properties at a given flood level subroutine 550 ' 560 INPUT "Enter start,end and incre»ent •;K1,K2,K3 570 IF Kl)= MINY THEN GOTO 620 580 PRINT 'Level specified is below" 590 PRINT 'fflinimuBi elevation in section " 600 INPUT "Re-enter specific flood level"; K1,K2,K3 610 GOTO 570 620 IF 0$="s" OR QJ="S" THEN GOSUB 1110 630 HFL=K1:K4=(K2-K1]/K3+1 640 FOR 1=1 TO M-1:A(I)=0:P(I)=0:T(I)=0:NEXT I 65»-fOR -J=l TO K4 660 K = M - 1 670 FO R I = 1 TO K 680 I F EL(I) >= HFL AND EL(I + l) )= HFL THEN GOSUB 880: GOTO 720 690 I F EL(I] >= HFL AND EL(I + !)'< HFL THEN GOSUB 910: GOTO 720 700 I F EL(I) < HFL AND EL(I + 1) )= HFL THEN GOSUB 950: GOTO 720 710 I F EL(I) < HFL AND EL(I + l] ( HFL THEN GOSUB 990: GOTO 720 720 NEX T I 730 AREA=0:PER=0:TOP= 0 740 FO R 1=1 TO M 750 AREA=AREA+A(I ) 760 PER=PER+P(I ) 770 TOP=TOP+T(I ) 780 NEX T I 790 I F 0$='s' OR 0$='S' THEN GOTO 820 800 PRIN T «2, TAB(2); USING "«««.««" ;HFL;:PRINT 12, TAB(12]; USING "««««It.«"; AREA; 805 PRIN T 12, TAB(22); USING "tm«.«"; PER; 810 PRIN T «2, TAB(36); USING 'Um.i'\ TOP:GOT O 840 820 PRIN T TAB{2); USING "«##.««";HFL;:PRINT TAB(12); USING •««»««.AREA; 825 PRIN T TAB(22); USING "«««««J"; PER; 830 PRIN T TAB(36); USING "«««««J"; TOP 840 HFL=HFL+K 3 850 I F HFL)K2 THEN GOTO 870 860 NEXT J 870 RETURN 880 'sub-subroutine to calc area and periaeters 890 A(I) = 0: P(I) = 0: ^(1) = 0

910 A(ir= ABS(.5 * (HFL - EL(I + D) ' 2 * ((CH(I + 1) - CH(I)) I (EL(I + 1) - EL(I])]) 920 T(I)=ABS({HFL-EL(U1))MCH(I+1)-CH(I))/{EL(I+1]-EL{I))) 930 P(I) = S0R{(HFL - EL(I + D) ' 2 + T(l)'2) 940 RETURN 950 A(I) = (.5 * (HFL - EL{I)) ' 2 * ((CH(I + l) - CH(I)] I (EL(I + I) - EL(I])]) 100

960 T(I)=ABS((HFL-EL(I])MCH(I+1)-CH(I))/(EL(I+1)-EL(I))) 970 P(I) = SOR({HFL - EL(I)) ' 2 + T(I)'2) 980 RETURN 990 A(I) = (.5 * (CH(I + 1) - CH(I)) * (2 * HFL - EL(I + 1) - EL(I])) 1000 T(I)=CH(I+1]-CH(I) 1010 P(I) = SOR(T(I)' 2 4 (EL(I + 1) - EL(I)] ' 2) 1020 RETURN 1050 ' 1040 ' output to file sub 1050 PRINT t2,AJ:PRINT «2, 1060 PRINT «2, TAB(2); "Stage Hf; TAB(15); "Area"; TAB(24); "Periiieter"; 1070 PRINT «2, TAB(39); "Top Width' 1080 PRINT «2, TAB(6); '(si)'; TAB(15); "(sq.i]'; TAB(26); -(m)'; TAB(42]; '(i) 1090 PRINT «2, 1100 RETURN 1110 ' output to screen sub 1120 CLS 1130 PRINT A$:PRINT 1140 PRINT TAB(2); "Stage Ht"; TAB(15]; 'Area"; TAB(24); 'Perimeter"; 1150 PRINT TAB(36); 'Top Width' 1160 PRINT TAB(6); '(»]"; TAB(15); "(sq.®)"; TAB(26); "(a)"; TAB(42); "(m]' 1170 PRINT 1180 RETURN mw^^m