sediment and ground water sampling

ISOTOPLTD

Eilat Peace LagoonSediment and Groundwater

Sampling Report

Prepared for: DHV

Prepared by: Avi EdriAgreement number: 538343

Date: 21. 2.16

11418- Sediment sampling report, peace lagoon Eilat- DRAFT FOR COMMENTS

Peace Lagoon Eilat- IsraelProject name:Peace Lagoon Eilat- IsraelSite location:

11418Project number:Royal Haskoning DHVCustomer:

Preparation, testing and certification

Approved and tested byWritten and edited byDateFile #Sharon Dviri & Yaara Rimon-BrandAvi Edri9.12.151Sharon Dviri & Yaara Rimon-BrandAvi Edri21.2.162

Distribution listCopy typeDatePrepared forCopy #

Draft for comments9.12.15DHV1Draft for comments9.12.15ISOTOP1Draft for comments21.2.16DHV1Draft for comments21.2.16ISOTOP1

Isotop company informationIsotope Ltd.

Head Office: 20 Ha'Yarok St. Kannot Industrial Park P.O.B. 2 GEDERA 70700, ISRAEL08-8697182Phone number:08-8697008Fax number:

[email protected]:www.isotop.co.ilWebsite:

11418- Sediment sampling report, peace lagoon Eilat- DRAFT FOR COMMENTS

http://www.isotop.co.il/

mailto:[email protected]

Table of Contents

1. Introduction.....................................................................................41.1. Area..............................................................................................52. Material and Methods.....................................................................62.1. Field Measurement......................................................................62.2. Laboratory Analysis......................................................................63. Result and Discussion.......................................................................83.1. Field Measurement......................................................................83.2. Laboratory Findings......................................................................93.2.1. PSD 93.2.2. Organic Matter 143.2.3. Sulfate and Sulfide 154.1. Methodology..............................................................................174.2. Results and discussion................................................................194.3. Laboratory results.......................................................................245. Appendix………………………………………………………..…25

FiguresFigure 1. Site location............................................................................................................................................5Figure 2. Map of the lagoon distribution into three main zones, including the sampling point location..............6Figure 3. S1 core, zone A.......................................................................................................................................9Figure 4. S1- Particle size distribution of both black and underlying layers in zone A.........................................10Figure 5. S2 core, zone B.....................................................................................................................................11Figure 6. S2- Particle size distribution of three main layers in zone B.................................................................12Figure 7. S3 core, zone C.....................................................................................................................................13Figure 8. S3- Particle size distribution of both top and underlying layers in zone C............................................14Figure 9. Findings of the OM content of the black and underlying layers...........................................................15Figure 10. Distribution of sulfate concentration..................................................................................................16Figure 11. G1- monitoring well structure............................................................................................................20Figure 12.G1- Groundwater level during 24h measurements.............................................................................21Figure 13. G2- monitoring well structure............................................................................................................22Figure 14. G1- groundwater level during 24h measurements.............................................................................23Figure 15. Lagoon water level during 24h measurements..................................................................................24

TablesTable 1. Field measurement findings....................................................................................................................8Table 2. S1- Particle size distribution of both black and underlying layers in zone A..........................................10Table 3. S2- Particle size distribution of three main layers in zone B..................................................................11Table 4. S3- Particle size distribution of both top and underlying layers in zone C.............................................14Table 5. Minimum and maximum water levels...................................................................................................21Table 6. Groundwater laboratory results............................................................................................................24

EquationEquation 1 OM content……………............................................................................................................................7Equation 2

water column…………….............................................................................................................18

1. Introduction

In 1967, the detailed plan for developing the eastern part of the city Eilat was approved for

the first time. Later, in 1990, the Institute for Marine engineering Research of Israel

(subsidiary of the Technion) published the first development feasibility report of the eastern

lagoon. In 1995, development works were completed and the eastern lagoon opened to the

public.

The lagoon, 300,000m3 of water that originates from the Red Sea. The main purpose of this

lagoon was to serve the hotels that are not located near the Red Sea shore, as well as to

become a new attraction and be used for recreation in the eastern interior part of the Eilat.

However, a couple of months after the opening of the lagoon, a significant decrease in the

quality of the lagoon water were observed. This was reflected by high turbidity as well as

the sinking and accumulating of dead organic material in the lagoon's bottom. This led the

planning authorities to withdraw their former permission for any further construction until

the water quality issues are resolved.

In September 2012, RHDHV Company provided a detailed plan for sampling and monitoring

the physical and chemical characteristics of the eastern lagoon. The measurements were

composed of three main parts; soil quality measurements, chemical/water quality

measurements, and hydraulic and bathymetric measurements.

Later on, in July 2015, RHDHV (the client), which was selected by the relevant authorities to

manage this project and in addition to promote this plan, hired ISOTOP Ltd (Isotop) to carry

out investigation of the sediments and the ground water on site.

This paper presents the findings for the sediments investigation only.

11418- Peace Lagoon Eilat- Sediment Sampling Report- DRAFT FOR REVIEW

CHAPTER A

1.1. Area

The “Peace” Lagoon is located in the eastern part of Eilat in Israel; about 500m north to the

Red Sea shore (fig. 1). The lagoon was founded on sandy soil layers that were imported from

external sources. The natural soil under this layer is characterized as Sabkha (Qp) soils or

Playa deposit soils (Qsp).

Figure 1. Site location.

The sampling work was conducted on three main zones that characterize the lagoon area

(fig. 2);

1. Zone A- Permanent open water. Boreholes S1, S4, S7 and S10.

2. Zone B- Intertidal. Boreholes S2, S5 and S8.

3. Zone C- Above the highest tide line. Boreholes S3, S6 and S9.


Figure 2. Map of the lagoon distribution into three main zones, including the sampling point location.

2. Material and Methods

2.1. Field Measurement

Four fixed parameters were measured for each measurement point;

Coordinate- The coordinates were measured using Garmin GPS, model eTrex 10 with an

accuracy of 3 to 5m. The GPS was adjusted to the Israeli Transverse Mercator (ITM).

Absolute height- Surface height above sea level was measured using a Stabila telescope

scale, model ATM 300.

Layer thickness- Layers thicknesses were measured using a simple scale measurement. The

resulting value represents the average thickness of three measurements per each layer

(n=3).

2.2. Laboratory Analysis

Cores sampling from the lagoon surface was carried out according to ISO 5667-19:2004. This

ISO served as a guideline for sampling sediment in the marine area, analysis of their physical

and chemical properties, monitoring purposes and environmental assessment. It

encompasses sampling strategy, requirements for sampling devices, packaging and storage

of sediments samples.


According to this ISO, the lagoon sediment was sampled by using a piston sampler. The

piston sampler has a piston contained within the sample tube, which moves upwards

relatively to the sample tube at some stage of the sampling process (Bastin and Davis 1909;

Stokstad 1939). In this project, we used a 1m long piston sampler with 5.8 cm diameter. The

soil core of each location was photographed and its lithology was documented. Specific

samples from specific locations were sent to the laboratory and the following characteristics

were analyzed;

Particle Size Distribution (PSD)

In three locations (S1, S2 and S3), sediments samples were taken from all three main layers;

top, black (middle) and bottom (clean/underlying/base). A total of 9 samples were analyzed

in the laboratory to determine the PSD of each layer. The samples were analyzed according

to standard method No. D-422. This method covers the quantitative determination of the

distribution of particle size in soils. The distribution of particle size larger than 75 µm was

determined by a sieving, while the distribution of particle size smaller than 75 µm was

determined by a sedimentation process, using a hydrometer to secure the necessary data.

At our request, the laboratory adjusted this current method to minimum value of 63 µm.

Organic Matter- In five locations (S1, S2, S4, S5 and S10), sediments samples were taken

from the black and bottom layers. A total of 10 samples were analyzed according to LOI

(Loss on Ignition) test. LOI calculates the organic matter (OM) content (%) by comparing the

initial weight of the sediment sample, before and after the sediment has been ignited. To

achieve this weight difference, the samples were dried at temperature of 105°C for a period

of 24 hours, weighed, ignited to 550°C and weighed again. The total solids calculation of

each sample was carried out according to standard method No. 2540EB.

The organic matter content (%) was calculated by using the following equation:

(1) :

Where TS105 is the total solids at 105° C (%) and TS550 is the total solids at 550° C (%).

Sulfate and Sulfide


In five location (S1, S2, S4, S5 and S10), sediments samples were taken from the black and

bottom layers. A total of 10 samples were analyzed in a laboratory to determine the

concentration of both sulfate (mg/kg) and sulfide (mg/L). The samples were analyzed

according to standard method No. 4500 SO42E and 4500 S2-F for sulfate and sulfide

respectively.

3. Result and Discussion

3.1. Field Measurement

The sampling points were located evenly, according to three main zones: A, B and C (fig. 2).

The absolute height average of each zone is -2.1, 0.54 and 1.4 m respectively (table 1).

Table 1. Field measurement findings

Location Coordinate (ITM) Absolute Height (m)

Top Layer Thickness*Avg.

(m)

Black layer Thickness*Avg.

(m)

S1 196785/384781 -1.41 <0.002 0.1S2 196860/384683 0.57 0.0146 0.071S3 196855/384676 1.81 0.11 N.DS4 196754/384907 -2.52 <0.002 0.093S5 196746/384953 0.42 0.029 0.038S6 196747/384957 1.15 0.027 N.DS7 196632/384861 -2.14 <0.002 0.17S8 196591/384863 0.63 0.015 0.053S9 196578/384867 1.24 0.18 N.D

S10 196560/384620 -2.52 <0.002 0.083

* n=3ITM Israeli Transverse MercatorN.D No Data

3.1.1. Layer Thickness

The thickness of the top layer of the soil was measured only in zones B and C. In these

zones, the top soil layer was sufficiently developed to be measured and sampled, without

disturbing or mixing the structure of the soil layers. The top soil layer was also identified in

zone A. However, this layer was found to be very thin, saturated and unstable, making it

impossible to take any measurements or samples to the laboratory by this method.

However, in the qualitative aspect, this layer thickness was estimated at less than 2mm and

as an un-cohesive silty-clay texture. The above physical properties of this layer were found

homogeneous in zone A. It is apparent that this layer's properties are determined in

accordance with the regional water stream regime and with the amount and the availability

of suspension particle.


3.2. Laboratory Findings

3.2.1. PSD

PSD analysis was carried out for three sampling points; S1, S2 and S3. These points are

located in the southeastern part of the study area ("Peace Lagoon") and represent zone A, B

and C respectively. Laboratory certificates appear in Appendix A.

S1- Laboratory findings indicate the presence of two main soil layers; Black (middle) and

underlying (bottom/base) layer. However, in most cases, the transition from the black layer

to the underlying layer was characterized by gradual tendency that creates (at least visually)

a new grey sub-middle layer (fig.3).

Figure 3. S1 core, zone A.

PSD results show that both of these layers are characterizing as sandy textured. The largest

segments were of particle size of 0.25-0.5mm (55%) in the black layer and 0.099-0.25mm

(59%) in the underlying layer (table2 and fig.4), meaning that the black layer contains a

much larger segment of coarse material compared with the underlying layer. this is showed

also by the distribution curves


Black Black layerlayer

Grey Grey (mixed) (mixed)

layerlayer

Bottom Bottom (clean) layer(clean) layer

Particle Size (mm)

Top Layer Black Layer Underlying LayerCumulative Distribution

(%)

Relative Distributio

n (%)

Cumulative Distribution

(%)

Relative Distribution

(%)


(%)


n (%)4-8

N.D

100 0 100 02-4 100 1 100 01-2 99 4 100 1

0.5-1 95 14 99 20.25-0.5 81 55 97 34

0.099-0.25 26 16 63 590.063-0.099 10 0.7 4 1.2

0.063> 9.3 9.3 2.8 2.8

Texture N.D Sand SandTable 2. S1- Particle size distribution of both black and underlying layers in zone A.

Figure 4. S1- Particle size distribution of both black and underlying layers in zone A.


S2- At this sampling point, three main sediments layers were observed, including a mix sub-

middle layer between the black to the underlying layers (fig.5).

Figure 5. S2 core, zone B.

The results show that both top and black layers are characterized as sandy textured, while

the underlying layer was characterized as loamy- sand. The texture difference is an

expression of the difference between the thin particle (<0.099mm) segment size (table 3

and fig.6).

Particle Size (mm)


(%)


(%)


(%)


n (%)


(%)


(%)4-8 100 0 100 0 100 12-4 100 0 100 1 99 21-2 100 1 99 1 97 4

0.5-1 99 6 98 7 93 110.25-0.5 93 67 91 61 82 40

0.099-0.25 26 22 30 23 42 240.063-0.099 4 0.5 7 1.4 18 2

0.063> 3.5 3.5 5.6 5.6 16 16

Texture Sand Sand Loamy Sand Table 3. S2- Particle size distribution of three main layers in zone B.


Black Black layerlayer

Mixed layerMixed layerBottom Bottom (clean) layer(clean) layer

Top Top layerlayer

Figure 6. S2- Particle size distribution of three main layers in zone B.

S3- At this sampling point, two main sediments layers were observed; top and underlying

layer, including a thin (<2cm) clay layer at the bottom of the borehole (fig.7). It is apparent

that the source of both of these layers is external. A qualitative assessment in the field

indicated that the top layer was composed from medium quartz particle while the

underlying layer was composed from coarse ted particle (most likely granite) from nearby

quarries.


Figure 7. S3 core, zone C.

As noted, at this point, only two sediments layers were observed. The results indicate that

both of these layers are characterized by large segments of medium to fine sand (0.099 to

0.5 mm). However, a relatively large segment (26%) of silt and clay (<0.063mm) was

measured at the top layer which is 9.2 times higher than at the underlying layer ,determined

a division into two textures groups; sandy and sandy-loam (table 4 and fig.8).

Soil structure images from borehole S4-S10 and logs description presented in Appendix B and C respectively

Table 4. S3- Particle size distribution of both top and underlying layers in zone C.


Top Top layerlayer

Clay Clay aggregateaggregate

Clay Clay layerlayer

Bottom layerBottom layer

Particle Size (mm)


(%)


(%)


(%)


(%)


(%)


(%)4-8 100 1

N.D

100 02-4 99 0 100 11-2 99 1 99 1

0.5-1 98 5 98 70.25-0.5 93 36 91 62

0.099-0.25 57 28 29 260.063-0.099 29 3 3 0.2

0.063> 26 26 2.8 2.8

Texture Sandy Loam N.D Sand

Figure 8. S3- Particle size distribution of both top and underlying layers in zone C.

3.2.2. Organic Matter

Laboratory results indicated mixed trend. On one hand, the results show that the content

average of OM (organic matter- %) in the black layers is 1.5 times higher than the content

average of OM in the underline layers. In addition, it was found that the content of OM in

the black layers of boreholes S1 (2.3%) and S5 (2.4%) is 1.7 times higher than the highest

value (1.4%) in the underlying layer of borehole S2 (fig. 9). On the other hand, in only 2 of 5

boreholes, the OM content was found higher in the black layer compared to underlying

layer. Statistical data analysis indicated on lack of statistical significance (p>0.05) between

these layers.


Comparison between the above boreholes show that the average of OM content of both

layers in borehole S5 is 1.1, 1.5, 2.3 and 2.3 times higher than in boreholes S1, S2, S4, and

S10 respectively.

Figure 9. Findings of the OM content of the black and underlying layers.

3.2.3. Sulfate and Sulfide

Laboratory results indicated the presence of sulfate only. In the samples taken from the

black layer at boreholes S1, S2, S4, S5 and S10, the concentration of the sulfide was not

higher than the lab detection threshold (0.1 mg L-1).

Although sulfate was observed in all five measurement points (fig. 10), none of the values

obtained crossed the acceptable 1threshold value for residual areas (1500 mg L-1).

Laboratory certificates of both sulfate- sulfide and organic matter appear in Appendix D.

1 According to the Primary threshold values contaminants in soils, The Israel ministry of environment protection, 2003.


Figure 10. Distribution of sulfate concentration.


CHAPTER B

4. Groundwater Quality and Groundwater Level

In order to examine the chemical and hydrogeological bonds between the lagoon water

(originating from the Red Sea) and local groundwater, a monitoring plan was carried out in

four main phases: installation, development, purging, field measurement and sample

collection.

4.1. Methodology

4.1.1. Installation

Groundwater monitoring wells (G1 and G2) were installed in accordance with the technical

specifications as submitted by DHV. The wells were drilled using a Boart Long year drilling

machine, model LX 6 (DB525). The installation was carried out using hollow- stem auger

with temporary casing.

4.1.2. Well development

After the monitoring wells were installed, development of the wells was carried out to

ensure maximum removal of fine sediment from the vicinity of the well screen. A well-

development effort generally serves to increase the effectiveness and the quality of future

measurements. Pumping out the fine sediment at this stage is necessary to significantly

reduce the turbidity of water, prior to the purging stage.

4.1.3. Purging and field measurement

The purpose of purging is to remove stagnant water that is stored inside the well casing, as

well as water in the formation immediately adjacent to the well, prior to the sampling of

monitoring wells in order to evaluate the quality of water in saturated zone.

Parameters of each partial water column were measured while purging to determine

stability. Three consecutive parameters were used to define stability;

Temperature

Electrical conductance

pH

In addition, groundwater level, salinity and dissolved oxygen were also measured.


4.1.4. Water level measurements

Ground water and Lagoon water levels were measured for 24h at three locations

simultaneously: monitoring wells G1, G2 and in the lagoon water. Water levels were

measured by using a water level logger: model HOBO-U20-001-01. The level loggers were

installed at the depth of 0.83m below water level in a monitoring well and in a stilling well

inside the Lagoon. The stilling well purpose was to dismiss the effect of waves on the water

level measurements and to prevent movement of the level logger by underwater currents.

The values were obtained in units of pressure (kPa), converted to water column (m), taking

into account the following parameters;

PLA-tx-local barometric pressure at a given time (kPa).

PM-tx - pressure measured by the level loggers at a given time (kPa).

Pw-tx- groundwater/lagoon water pressure at measurement location at a given time (kPa).

ML- monitor location relative to sea level (m).

WL- tx - water level relative to sea level (m).

To find the value of water column (m) relative to one unit of pressure (1kPa), the following

equation was used;

(2):


4.1.5. Sample collection

Sample collections were taken using an Eijkelkamp 12vdc peristaltic pump. The volumetric

flow rate was calibrated to 450 ml min -1, in order to minimize agitation and aeration of the

wells water while sampling. Water samples were collected into four bottles for analysis of

nitrate, nitrite, ortho-P and silica in the analytical laboratory.

4.2. Results and discussion

4.2.1. Monitoring well- G1

Well G1 is located in the northern part of the East/Peace Lagoon (x: 196731/ y: 385041),

approximately 70m north to the intertidal zone, at a height of 4.94m AMSL (Above Mean

Sea Level). Well installation was carried out to depth of 8.64m, 4.22 m below the water

table (fig 11).


Figure 11. G1- monitoring well structure.

A week after the monitoring well was installed and developed (57.7L of turbid water had

been pumped out), a qualified drinking water sampler (by the Israeli Ministry of Health)

insured stabilization of the groundwater by measuring temperature, electrical conductance,

pH, salinity and dissolved oxygen to a stable value during the purging process. The final

values obtained were 23.8c, 61.0mS, 7.22, 41.2 PSU and 4.4 mg l-1 respectively.

Groundwater levels (24h)-the results indicate water levels variations in a cycle period of 12h

(fig 12). During measurement of 24h period, the water table level dropped twice to a


minimum value of 0.37 and 0.4m AMSL at 3:00 p.m. and 3:00 a.m., respectively. Similarly,

the water table level rose to maximum values of 0.73 and 0.79m AMSL at 9:00p.m. and

9:15a.m., respectively. The largest gap between the above is 0.39m.

In addition, the results show that the water table rose between maximum values

(ht9:15a.m.>ht9p.m.) and minimum values (ht3a.m.>ht3p.m.) periodically. However, the current data is

not sufficient to determine a statistical trend (table 1).

Figure 12.G1- Groundwater level during 24h measurements.

Table 5. Minimum and maximum water levels

location High Tide (m) Low Tide (m)

G1 0.736 0.794 0.375 0.4

G2 0.229 0.151 0.165 0.257

Lagoon 0.315 0.268 -0.616 -0.776

4.2.2. Monitoring well- G2

Well G2 is located in the southern part of the East/Peace Lagoon (x: 196693/ y: 384571),

about 100 m south of the intertidal zone, at a height of 2.75m AMSL. Well installation was

carried out to a depth of 6.8m, 3.4 m below the water table (fig 13).


Figure 13. G2- monitoring well structure.

After the monitoring well was installed and developed (44L of turbid water had been

pumped out), a qualified drinking water sampler (by the Israeli Ministry of Health)insured

stabilization of the groundwater by measuring temperature, electrical conductance, pH,

salinity and dissolved oxygen to a stable value during the purging process. The final values

obtained were 27.5c, 50.5mS, 7.35, 33.3 PSU and 5.5 mg l-1 respectively.

Groundwater levels (24h) - similar to the measurement results that were received in well

G1, the measurement results of well G2 water levels varied in a cycle period of 12h (fig 14).


However, it was found that the gap between maximum level (0.257m AMSL) and minimum

level (0.151m AMSL), was 2.9 times smaller than the obtained gap in well G1.

In addition, the results indicated heterogeneity trend in the increase and decrease of the

water. For example, an increase of the water between 6:00 a.m. to 12: 00p.m. was

composed from temporary frequent water table drops and vice versa, that is different from

the continuous and homogeneous periodic structure that characterizes well G1.

Figure 14. G1- groundwater level during 24h measurements.

4.2.3. East lagoon

Sea levels (24h) - the lagoon water level was measured simultaneously to groundwater

levelsmeasurements (G1, G2). The measurements were carried out at the northern part of

the lagoon, in the permanent open water (x: 196739/ y: 384891).

The level logger was installed in a stilling well made of a perforated well screen relatively

close to the lowest tide point, at a depth of 0.83m below sea level and 0.23m above the

lagoon bottom (fig 15). Since the lagoon water level is not fixed in time, an arbitrary

reference point was determined, after the installation of the measurement device, when the

lagoon water level was at 1.06m above the lagoon bottom. This reference point was also

used as a comparative reference point to the ground water measurements.


Measurement results indicate water levels variations in a cycle period of 12h, similar to the

level cycle measured at G1 and G2. The gap between the maximum level (0.315m) and the

minimum level (-0.77m) was 1.04m, 3.34 and 9.8 times larger than the gap that was

obtained at well G1 and G2, respectively.

Figure 15. Lagoon water level during 24h measurements.

4.3. Laboratory resultsTable 6. Groundwater laboratory results

Site Silica (µmol/l) NO3 (µmol/l) NO2 (µmol/l) PO4 (µmol/l)

G-1 224 2.7 2.4 3.1

G-2 153 3.5 1.1 3.6

Laboratory certificates appear in Appendix E.


sediment and ground water sampling

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