Felixstowe Peninsula Project - Green Suffolk · IP1 2BX Felixstowe Peninsula Project Concept Report...

Felixstowe Peninsula Project

Concept Report

10th March 2017

Suffolk Holistic Water Management Project

379642 01 B

http://pims01/pims/llisapi.dll/open/2108618170

Mott MacDonald

22 Station Road Cambridge CB1 2JD United Kingdom T +44 (0)1223 463500 F +44 (0)1223 461007 mottmac.com

Suffolk County Council, Endeavor House, 8 Russell Road, Ipswich, IP1 2BX

Felixstowe Peninsula Project

Concept Report

10th March 2017

Suffolk Holistic Water Management Project

Mott MacDonald | Felixstowe Peninsula Project

379642 | 01 | B | 10th March 2017 http://pims01/pims/llisapi.dll/open/2108618170

Issue and Revision Record

Revision Date Originator Checker Approver Description

A 26 Jan 17 D Mistry D Ocio P Ede First Issue

B 10 Mar 17 D Mistry D Ocio J Pawson

A Kirby Second Issue

Information class: Standard

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Forecasts presented i n this document were pr epared usi ng Data and the report is dependent or based on D ata. Inevitabl y, some of the assumptions used to develop the for ecasts will not be realised and unantici pated events and circumstances may occur. C onsequentl y M ott MacDonal d does not guarantee or warr ant the concl usi ons contained i n the repor t as there are li kel y to be differ ences between the for ecas ts and the ac tual results and those di ffer ences may be material. Whil e we consi der that the infor mation and opini ons gi ven i n this r eport are sound all parti es must rel y on their own skill and j udgement when making use of it .

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Contents

Executive summary 1

1 Introduction 2

2 Scope of Work 4

3 Methodology 5

3.1 Inflow series 5

3.2 Working hypotheses 8

3.2.1 Current useable storage of Kings Fleet: 8

3.2.2 Pump balancing storage 12

3.2.3 Water Quality: 12

3.2.4 Environmental flow requirements: 13

3.2.5 Required level of service: 13

3.2.6 Climate change allowance: 13

3.2.7 Pumping capacity: 14

3.2.8 Demand profile: 14

3.2.9 Demand values: 14

3.2.10 On-farm storage: 15

3.3 Water balance model 16

3.4 Demand centre requirements 17

4 Results 18

4.1 Sizing 18

4.1.1 Scenario A 18

4.1.2 Scenario C 22

4.2 Delivery Centre Analysis 25

4.3 Pumping Capacity 26

4.4 Pumping Operation 27

4.5 Resilience of the system 30

4.6 Optimisation of storage volume and pumping capacity 33

5 Conclusions 35

5.1 Results and conclusions 35

5.2 Recommendations 35

Appendices 37



A. Background material on the inflow series 38

B. Annual average inflow, supply and surplus 39

C. Demand centre analysis (Scenario C) 42

D. Delivery point location plan 47

Mott MacDonald | Felixstowe Peninsula Project 1


Executive summary

The Kings Fleet is part of the drainage system implemented in the Felixstowe Peninsula to

enhance agricultural production. As flows are currently pumped to the River Deben mouth, the

Suffolk Holistic Water Management Group has suggested using this surplus water to improve

and expand irrigation in the surrounding area. This would involve the construction of new

reservoir/s with enough capacity to provide resilience against the driest year in 20 years.

The annual irrigation demand from local farms has been estimated at 740Ml. A detailed water

balance model has been developed for the period 1970-2015. This model is based on a

simulated inflow series to the Kings Fleet provided for this report. The purpose of the water

balance model is to determine seasonal variability of irrigation demand and quantify the transfer

of water to the farms. It has been applied to determine the required storage capacity to meet the

expected level of service, which has been estimated as 510 to 550 mega litres distributed

between the Kings Fleet and the farms. Pumping capacity from the Kings Fleet needs to be 5 to

6Ml/d to meet storage requirements.

With this infrastructure, there would still be some deficit in case of extreme droughts, like the

ones recorded in the calendar years of 1991 and 1997, or if climate change increases the

frequency of drought conditions in the future. To provide water beyond a 1/20-year drought

event, there would need to be significant additions to the proposed infrastructure.



1 Introduction

The Kings Fleet is a water body located near the mouth of the River Deben which is

approximately 2.7km north of the port town of Felixstowe in Suffolk (NGR: TM318384). The

Kings Fleet measures approximately 1.5km in length with an approximate average width of

30m. The Kings Fleet receives inflows from the Falkenham Brook and a series of farm drains.

Due to its size, it is used by local anglers and has significant areas of reed bed, meaning it has

characteristics similar to a wetland. Figure 1 provides an overview of the size and location of

Kings Fleet. It should be noted that a catchment area was not derived as part of this report as

the area used to generate the simulated inflow series to Kings Fleet (discussed in Section 3.1)

was not provided. Whilst it may be possible to approximate a catchment area it is unlikely to be

accurate due to the contribution of farm drains to the Kings Fleet.

Figure 1: Kings Fleet location

Source: Mott MacDonald

The Holistic Water Management Project (HWMP) is an initiative led by Suffolk County Council

with the aim of linking different aspects of water management to alleviate flooding, build

resilience against drought, provide more reliable water resources for all and improve water-

based ecosystems. The HWMP is currently carrying out a pilot study focussed on the Deben

catchment. The Project Board has set up six working groups, to take forward various aspects of

the pilot study:

● Felixstowe Peninsula



● Debenham Flood Risk Management

● Channel Morphology & WFD

● Reservoir Planning & Consent

● License Trading & Abstraction Reform

● Aquifer Recharge

The Felixstowe Peninsula Project Sub Group of the HWMP wants to investigate options to make

use of surplus flows at the Kings Fleet. The primary use being considered at this stage is for

spray irrigation on nearby farms, but water could potentially also be made available for

environmental support or public water supply through provision of appropriate pipeline

connections.

The Felixstowe Peninsula Project Sub Group consists of the following key members:

● Suffolk County Council (SCC)

● Environment Agency (EA)

● East Suffolk Internal Drainage Board (IDB)

● East Suffolk Water Abstractor’s Group (ESWAG)

● Natural England (NE)

● Anglian Water

The discharge of flows from the King’s Fleet into the River Deben is the responsibility of East

Suffolk IDB under their water level and flood risk management role. Currently all inflow to the

Kings Fleet is pumped into the River Deben through an IDB pumping station located at the

eastern end of King’s Fleet. Providing that any necessary environmental flows to the Deben are

maintained there is therefore the potential to utilise this water that is currently discharged to tide

via the IDB’s pumps to supply landowners, for spray irrigation, in an area where no other water

resources are available.

Ownership, operation, and maintenance of any scheme is likely to be taken on by the East

Suffolk IDB (Water Management Alliance). The intention would be that a single abstraction

Licence will be held by the IDB (for ‘private water undertaking’). The East Suffolk IDB would

operate the scheme as a commercial undertaking; the unit cost at which water can be supplied

under this scheme is therefore of critical importance to the viability of the proposal.

Inflow to Kings Fleet is generally highest during the winter period, whereas irrigation demand is

concentrated during spring and summer. In order to meet the annual water demands it will be

necessary to provide seasonal storage of abstracted flows to allow use during the periods of

high water demand.

This report details outputs from a hydrological simulation to identify the infrastructure required

for using the surplus inflows to the Kings Fleet to meet local agricultural demand. The scope for

this work is outlined in Chapter 2. Using a simulated inflow series to the Kings Fleet, presented

in Chapter 3.1,and fixed monthly demand values, a water balance model was developed to

replicate the movement of water throughout the system. This model is outlined in Chapter 3.3.

Results from use of the model are presented in Chapter 4, with conclusions and

recommendations in Chapter 5.



2 Scope of Work

The intent of this report is to demonstrate if surplus inflows to Kings Fleet are sufficient to meet

local agricultural demands during the irrigation period. Consideration is given to how surplus

water would be stored at Kings Fleet and/or on farms, pumping capacity limitations,

environmental flow requirements and upstream abstractions. The central requirement of the

calculations completed was to determine if the surplus flows, given the necessary infrastructure,

could provide the Level of Service (LoS) required. This level of service has been defined as no

failure to meet demand for the driest year in 20 years. Thus, the scope of this work was to

determine if agricultural demand could be serviced during a 1/20 year drought event.

To determine if inflows to the Kings Fleet would be sufficient to meet the required LoS it was

necessary to develop a reservoir water balance to run a range of different scenarios. These

scenarios were designed to test if the required LoS could be met by changing the storage at

either Kings Fleet or the on farm storage reservoirs.

The scenarios tested are listed in Table 1. Outputs from the scenario runs are detailed in

Chapter 4.

Table 1: Scenarios tested in this study

Option Storage capacity at Kings Fleet

Daily pumping capacity On-farms storage capacity

A – Storage at Kings Fleet

Varied as required to achieve the LoS

Fixed by peak demand minus the attenuation provided by the on-farm storage.

Fixed at two days of peak demand.

C – On farm storage (9 storage reservoirs)

Fixed at current capacity

Varied as required to achieve the LoS.

Varied as required to achieve the LoS


An intermediate Option B has not been assessed at this stage, but may be defined and

developed following discussion of the results of this report with the project stakeholders.



3 Methodology

To analyse if inflows to Kings Fleet are sufficient to meet agricultural demands, it is necessary to

understand the:

● Operation of the Kings Fleet. It receives inflows fron the drainage catchment and provides

pumped water to the on farms storage. Losses from surplus inflows, environmental flows and

surplus water to the River Deben also need to be accounted for.

● Operation of on farms storage. It receives pumped water from the Kings Fleet and supplies

the required irrigation demand.

Following this analysis it is possible to determine what different options are available to most

effectively capture and use the water inflowing to the Kings Fleet. A simple schematic was

developed to illustrate the different components of the water supply system to the farms from

Kings Fleet. This conceptulisation of the system is presented in Figure 2 below:

Figure 2: Schematic of the relationship between Kings Fleet and farm demand


It should be noted that the model does not account for direct evaporation or rainfall from/to the

reservoir as the amount of losses/gains is not considered to be significant.

3.1 Inflow series

The inflow data was the basis of the water balance and is presented in Figure 3. The inflow

series is a simulated data series produced by the Environment Agency (EA) using the

CATCHMOD V2.1 model. It underpins the water balance model, and therefore, has a large



relevance on the outcome. Detailed information on how the model was developed has been

provided by the EA and is presented in Appendix A. Inputs to the model were:

Weekly potential evapotranspiration (MORECS)

Locally gauged rainfall data (October 1st 1970 to September 30th 2015)

Flows gauged at Falkenham and Kings Fleet pumps. Check completed against other

gauges (Holesley, Brantham, Playford etc.)

There is good confidence in the model due to the data for the simulated series being calibrated

using the gauged discharge from the land drainage pumps. Although not as reliable as gauged

flow data, this data provides a good basis to determine the validity of the simulated flow.

Findings from the EA research into this highlighted that the simulated series had good

calibration against pumped gauged data and nearby gauging stations. The model also

replicated summer baseflow conditions effectively.

Whilst robust given the available data, it should be noted that there are limitations with the

simulated inflow series which should be considered when analysing outputs from the water

balance. Specifically, the simulated series has:

Vulnerability to dry winters (i.e. overestimates flow)

Underestimates runoff from marsh areas

The Q50 is 10-15% below what is thought to be the actual flow

Figure 3: Simulated inflow series to Kings Fleet (1970-2015)

Source: Environment Agency

Further to the information provided by the EA, a check of the inflow series was completed for

the purposes of this report. Gauged flow data was taken from Holton (35013) and Farnham

(35003) via the National River Flow Archive (NRFA) website. These two gauges were selected

as they are also in Suffolk, have a similar catchment size to Kings Fleet and a similar baseflow

index (approximately 0.30). As part of this analysis flow duration curves were compared to



assess how comparable the two gauged flow series are with the Kings Fleet simulated series.

The outputs from this analysis are presented in Figure 4.

Figure 4: Flow duration analysis of Kings Fleet simulated series vs Holton and Farnham

Source: NRFA, Environment Agency and Mott MacDonald

As can be seen in Figure 4 there is a poor correspondence between the two gauged stations

and the Kings Fleet simulated series. Further analysis of the gauged flow series and catchment

characteristics shows that the two gauged data series have different geological and soil profiles

in the upper reaches. Holton and Farnham consist largely of impermeable clay, whereas Kings

Fleet is comprised of permeable gravels. This is consistent with the observed differences in the

flow duration curves which show the gauged data to have higher flows (i.e. more runoff) in wet

periods (i.e. flow>Q10) while Kings Fleet retains a higher baseflow across the data sets.

The previous analysis evidences the difficulties of transposing information between catchments

with different physical properties, which precludes an adequate validation of the modelled flow

series. However, overall there is good correspondence to the pumped gauged data which

provides reasonable confidence in the data.



3.2 Working hypotheses

The water balance model requires several inputs which are fixed parameters. These inputs are:

Current usable storage in Kings Fleet

Pump balancing storage

Water quality

Environmental flow requirements

Interpretation of the required level of service

Climate change allowance

Pumping capacity

Demand profile

Demand values

Minimum on-farm storage capacity

For each of these inputs a working hypothesis is provided so that there is an understanding of

the assumptions that have been made to develop the water balance model.

3.2.1 Current useable storage of Kings Fleet:

Under Option C the useable storage volume at the King’s Fleet is assumed to be fixed at the

current capacity. The current operation of the King’s Fleet has therefore been investigated to

assess the existing useable storage capacity.

3.2.1.1 Useable storage of King’s Fleet

Flow from the King’s Fleet passes over a weir into the King’s Fleet pump sump, and from here is

pumped into the River Deben via an IDB pumping station (refer to Figure 5 for location plan).

The water level of the King’s Fleet is controlled by the weir at the outfall into the IDB pump

sump. The level of the weir is managed by agreement with Kingsfleet Anglers according to the

following levels to ensure that surrounding arable land does not lay water logged during the

winter months:

● -0.356mAOD (-14” AOD) between April 14th and September 14th

● -0.584mAOD (-23” AOD) from 15th September to the 13th April

It is understood that except for this seasonal management of weir level the water level in the

King’s Fleet does not vary significantly under the typical range of inflows. It should, however, be

noted that during flood inflows the water level would be expected to rise in accordance with the

increased head required to pass these flows over the outfall weir.



Figure 5: King’s Fleet location plan

Source: Contains Ordnance Survey data Crown Copyright and database right © 2016

The storage volume above the normal winter level of -0.584mAOD has been estimated through

analysis of the LiDAR DTM (refer to Figure 7). This indicates that the storage volume within the

normal seasonal level variation (i.e. between normal winter and summer levels) is approximately

12Ml.

However, the water balance model indicates that if a storage volume of 12Ml at King’s Fleet is

assumed then the volume stored here would be required to fluctuate significantly to balance

inflows and abstraction flows, with a maximum daily level change of approximately 0.225m.

Refer to Figure 6 for a detailed histogram showing the relative frequency of daily water level

variations.

This estimated rate of water level fluctuation in the Kings Fleet is understood to be unacceptable

both to the Kingsfleet anglers and in terms of environmental impact, and therefore the current

useable storage of the King’s Fleet itself is assumed to be zero.

King’s Fleet

King’s Fleet IDB pump sump

Weir outfall from King’s Fleet to

King’s Fleet IDB pump sump



Figure 6: Daily level change histogram – 12Ml storage at King’s Fleet


Figure 7: King’s Fleet stage-storage curve


0.0%

0.1%

1.0%

10.0%

100.0%

0 0.025 0.05 0.075 0.1 0.125 0.15 0.175 0.2 0.225 0.25

Rel

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Daily level change histogram - 12Ml storage at King's Fleet

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-0.7 -0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5

Surf

ace

are

a (m

²)

Vo

lum

e (m

³)

Stage (mAOD)

King's Fleet Stage-Storage

Normal winter level (-0.584mAOD) Normal summer level (-0.356mAOD)

Typical surrounding ground level Volume above normal Winter level (-0.584mAOD)

Surface area (measured from LiDAR DTM) Surface area (assumed constant below -0.3mAOD)



3.2.1.2 IDB Pump Sump

The IDB pump sump is currently used to balance flows for the IDB pumping station. This area

therefore currently experiences significant level fluctuations, and could potentially be used to

balance inflow for the new abstraction scheme.

The degree of level variation is determined by the “pump on” and “pump off” levels for the IDB

pumping station. These are referenced to a local datum, and are set as follows:

● Pump on - 1.5 mALD

● Pump off – 1.3 mALD

It has been necessary to relate this local datum to ordnance datum in order to estimate the

surface area, and hence volume, of the pump sump. A site visit was carried out at which the

water level in the King’s Fleet was at the normal winter level and the water level in the pump

sump was observed to be lower than that in the King’s Fleet. On this basis it appears that “pump

on” level is at or below normal winter level, and it is therefore assumed that the “pump on” local

datum level (1.5mALD) is equal to normal winter level of -0.584mAOD. Based on this offset the

“pump off” local datum level (1.3mALD) is equivalent to -0.784mAOD.

The storage volume between “pump on” and “pump off” levels has been estimated through

analysis of the LiDAR DTM (refer to Figure 8). This indicates that the storage volume is

approximately 3Ml.

For Option C the useable storage at King’s Fleet is therefore assumed to be 3Ml.

Figure 8: IDB Pump Sump stage-storage curve


0

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IDB Pump Sump Stage-Storage

Estimated pump off level Estimated pump on level

Estimated pump High High on level Volume above pump off level

Surface Area (measured from LiDAR DTM)



3.2.2 Pump balancing storage

It is common to provide balancing storage at pumping station intakes in order to reduce the

frequency with which it is necessary for the pumps to operate. It is assumed at this stage that 1

Ml/day storage will be provided between “pump on” and “pump off” levels. At the estimated

pumping rate of 5 to 6 Ml/day this would ensure that the pumps can operate for a minimum of

approximately 4 hours between “pump on” and “pump off” levels.

This balancing storage is additional to the storage represented in the water balance model;

therefore, the storage at King’s Fleet represented in the water balance model is reduced by 1 Ml

to account for this.

3.2.3 Water Quality:

It has been assumed in this study that water quality within the Kings Fleet and King’s Fleet

pump sump will be suitable for irrigation use at all times.

East Suffolk IDB are monitoring the electrical conductivity (EC)at the IDB pump trash screen to

track trends in salinity at this location (refer to Figure 9 for details). This indicates that at times,

electrical conductivity is potentially at levels that would require restrictions on use, with levels

peaking during pumping at between 1.5 dS/m and 3 dS/m (refer to Table 2 for details of degree

of restriction of use). It is understood that the project subgroup currently envisage that it may be

possible to resolve quality issues using measures such as configuring the pump to take water

from the surface only and maintaining higher water levels in the soke dyke (where saline ingress

is most pronounced). There is a possibility however that potential abstraction volumes could be

restricted if it is necessary to introduce an automatic cut out based on EC levels.

Table 2: FAO guidelines for interpretation of water quality for irrigation

Degree of restriction on use

None Slight to Moderate Severe

Electrical Conductivity, ECw (dS/m) < 0.7 0.7 – 3.0 > 3.0

Source: Water quality for agriculture, Food and Agriculture Organisation of the United Nations



Figure 9: King’s Fleet Electrical Conductivity

Source: East Suffolk IDB and Paul Bradford

3.2.4 Environmental flow requirements:

Any requirement for environmental flow to be maintained in to the River Deben has been

assumed to be covered by the southern catchment of the King’s Fleet. This part of the King’s

Fleet catchment is not part of the EA modelled flow data. Therefore, no environmental

requirements are introduced in the water balance. However, an additional element was added

to the water balance model so that if there was a need for environmental flow to be directly

accounted for in the water balance model in the future this could be modelled.

3.2.5 Required level of service:

Defined as no failure for the driest year in 20 years. This was interpreted as no more than 2

failures during the 45 years of simulation.

3.2.6 Climate change allowance:

No climate change allowance is considered in the modelled flow data; the water balance model

therefore considers present day conditions only.

The UKCP09 key findings have been reviewed to make a broad assessment of the possible

impacts of climate change. It should be noted that these projections were produced on the basis

of scientific information known at the relevant time and are subject to change;

The key findings for the medium emissions scenario for the East of England region are:

● 90% probability that there will be a small increase in summer and winter precipitation

● 50% probability that there will be a small increase in winter precipitation and a small

decrease in summer precipitation

0

0.5

1

1.5

2

2.5

3

3.5

Elec

tric

al C

on

du

ctiv

ity

(dS/

m)

Date

Electrical Conductivity at King's Fleet



● High intensity rainfall events will become more common

3.2.7 Pumping capacity:

The required pumping capacity was calculated based on the storage requirements at Kings

Fleet and the on-farm demand centres, based on the results from the water balance model.

Further detail about the pumping capacity is provided with the results in Chapter 4.

3.2.8 Demand profile:

A monthly demand profile has been provided for this study by the Environment Agency and Paul

Bradford. This profile was developed based on a study of historic abstraction returns for the

area, and is shown in Figure 10. It should be noted that annual demand values were provided

separately from the demand profile, so the monthly demand values were calculated by applying

the below to the yearly demand.

Figure 10: Proportional split of demand across each month for the period 2006-2015

Source: Environment Agency and Paul Bradford

3.2.9 Demand values:

Annual demand values were provided for this study by the East Suffolk Water Abstractor’s

Group (ESWAG). These values are based on initial expressions of interest from agricultural

water users within the study area. In total there are eleven demand centres (discussed in

Section 3.4), with a sum demand from all the centres totalling 740 mega litres.

Table 3: Annual demand at each demand centre

Demand Centre Annual Demand (Ml) Percentage of total demand

A 150 20.27%

B 50 6.67%

C 45 6.08%

E 50 6.76%

F 150 20.27%

G 50 6.76%



Demand Centre Annual Demand (Ml) Percentage of total demand

H 10 1.35%

K 150 20.27%

M 20 2.70%

N 50 6.76%

O 15 2.03%

Source: East Suffolk Water Abstractor’s Group (ESWAG)

This total annual demand was split proportionally based on the information provided in Figure

10 to derive the monthly demand profile. To run the mathematical model, daily values were

needed based on the above. Total daily demand values are presented in Table 4.

It should be noted that the values provided represent average demand. In reality, the daily

demand would vary from year to year depending on weather conditions. For example, demand

would be likely to increase during consecutive dry years, and decrease where rainfall is above

average for a year or more. The model does not consider annual variability in demand.

Table 4: Total demand profile (daily demand values)

Month Daily Demand (Ml/d)

January 0.00

February 0.00

March 0.11

April 1.42

May 4.50

June 6.13

July 5.49

August 3.84

September 2.29

October 0.40

November 0.00

December 0.00

Source: Derived from monthly demand profile and total annual demand

3.2.10 On-farm storage:

Through discussion with ESWAG nine delivery points were identified to supply water to the

eleven demand centres. Most demand centres have an individual delivery point, but the

following demand centres are in close proximity to each other and were therefore assumed to

share a single delivery point:

● B & C

● G & N

On-farm storage was assumed to be located at the nine identified delivery centres. Refer to

Appendix D for a map of the delivery centres.

For Scenario A the total on-farm storage capacity is assumed to be equal to two days of peak

demand, which equates to 59.4 Ml. Peak daily demand values for each delivery centre (based

on an estimate of the maximum number of rain-guns likely to be in use at one time) were

provided for this report by Paul Bradford. These values are presented in Table 5.



For Scenario C the required on farm storage has been determined from the results of the water

balance model in order to limit the number of supply failures during the 45 years of simulation to

a maximum of two.

Table 5: Estimated maximum daily demand for each on-farm delivery centre

Delivery Centre Peak daily demand (Ml)

A 4.75

B & C 4.75

E 2.38

F 4.75

G & N 4.75

H 1.19

K 4.75

M 1.19

O 1.19

TOTAL 29.7

Source: Paul Bradford

3.3 Water balance model

In order to establish the required infrastructure, a mathematical model was needed to simulate

the movement of water throughout the system. The following equations were used to determine

the storage at Kings Fleet and on-farm storage respecitvely:

Kings Fleet water balance:

SK2 = SK1 + I – ER – PW – SW

(which can vary between 0 and the stated storage capacity at Kings Fleet)

Where,

– SK = Stored volume at Kings Fleet at the beginning of the day

– I = Inflow to Kings Fleet

– ER = Environmental requirement fulfilled each day. They have prioirty over pumping and

they must always be satisfied unless Kings Fleet is empty.

– PW = Pumped water to the on-farm storage. Water available at Kings Fleet once the

environmental requirements are satisfied. Limited by the maximum pumping capacity.

Water is only pumped if the on-farm storage is not full and untill it is replenished.

– SW = Surplus water that is pumped to the estuary if the Kings Fleet is full at the end of

the day.

On-farm storage equation:

SF2 = SF1 + PW – DS

(which can vary between 0 and the stated capacity at the on-farm storage)

Where,



– SF = Stored volume on the farms at the beginning of the day

– PW = Pumped water to the on-farm storage from the Kings Fleet.

– DS = Irrigation demand supplied from the on-farm storage

Given the above, the model is defined as having three main parameters which confine the

amount of inflow to Kings Fleet which gets converted to agricultural water supply. These are:

– Stoage capacity at Kings Fleet

– Daily pumping capacity

– On-farm/s storage capacity

It should be noted that further analysis was completed for the on-farm storage capacity. This

analysis considered nine demand centres as defined in the scope. Each demand centre

represents an on-farm storage facility that would need to be supplied from Kings Fleet. Further

details about the specific requirements of each of the demand centres is presented in Section

3.4.

By adjusting the parameters it was possible to generate simulated stored volumes and supply

values for the 45 year period (1970-2015) of inflow data to the Kings Fleet that was provided by

the Environment Agency for this study.

Adjusting the parameters allowed for the different scenarios listed in Table 1 to be tested. To

demonstrate the amount of storage required at Kings Fleet and/or on-farm reservoir sites a

number of outputs were generated from each model run.These outputs include:

Graphical evolution of the stored volume at Kings Fleet and the on-farm storage

Average annual demand supplied

Average annual surplus at Kings Fleet

Further to this, average annual environmental requirements could be generated if a minimum

environmental flow was required.

Outputs also allow for analysis of the frequency of operation and average annual volume of

pumped water. For each scenario analysis is completed on the LoS for the 45-year period. This

analysis includes:

Number of years when the demand is not totally fulfilled

Percentage of irrigation demand volume not met

Percentage of days when irrigation demand is not served

It should be noted that the Irrigation Deficit (ID) is calculated by the demand minus actual

supply. Calculating the ID is necessary to confirm if the level of service has been met in each of

the different scenarios listed in Table 1.

The results from the analysis are provided in Chapter 4 of this report. Conclusions and

recommendations are provided in Chapter 5.

3.4 Demand centre requirements

In this report ‘on-farm storage’ refers to the total distributed storage required across all demand

centres. The total annual demand across all farms is 740Ml. It should be noted that for Scenario

C each farm will be served by their nearest ‘delivery centre reservoir’. This is to ensure that

more water is stored nearest areas of high demand, and less where the demand is not so great.



4 Results

4.1 Sizing

This chapter presents results from the model developed using the simulated inflow series (see

Section 3.1). The results are separated based on the two different scenarios. Further detail

about the required annual inputs for the demand centres is provided in Section 4.1.2 for

Scenario C.

It should be noted that all results from the model presented in this report are based on annual

water years. A water year starts and finishes on the 1st of October. For example, the year ‘1970’

would be from October 1st 1970 until September 30th 1971. The reason a water year was

selected because this is the start and end of the simulated inflow series. Thus, the model

incorporates all data and assumes that Kings Fleet and the on-farm storage reservoirs start full.

4.1.1 Scenario A

Scenario A was premised on a variable storage value for Kings Fleet, with fixed on-farm storage

sufficient to cover two days of peak demand. The parameters listed in Table 6 allow for

sufficient supply to meet the minimum LoS required by the farms (i.e. 1/20-year drought

conditions).

There is a single solution for this scenario as the two variable parameters are independent of

each other:

● Pumping capacity – determined by the flow rate required to meet peak demand (allowing for

attenuation by the on-farm storage)

● King’s Fleet Storage – determined through the water balance model to achieve the minimum

LoS

Table 6: Parameter values for Scenario A (storage at Kings Fleet)

Parameter Value Comments

Kings Fleet Storage 451 Ml Minimum storage required to meet minimum LoS

On farm storage 59.4 Ml Two days of peak demand

Pumping Capacity 5 Ml/day Minimum value to meet the peak irrigation demand


The annual average values for inflow, supply and surplus are provided in Appendix B. Within the

45-year period, there were two years where there was a failure to meet on-farm demand. These

years were 1990 and 1996. It should be noted that there are further years where storage at

Kings Fleet is zero. During these years demand is met by the on-farm storage (i.e. 1990 and

1996 are the only water years where demand is not met). The evolution of storage at Kings

Fleet over the modelled period is shown in Figure 11.



Figure 11: Storage at Kings Fleet for the modelled period for Scenario A


In total 33045 Ml of supply was provided, with a failure to meet 240 Ml of demand over the 45-

year period. This equates to 0.72% of demand not being met over 45 years. There was a total of

105 days where supply did not meet demand over the period which equates to failure on 0.64%

of days during the 45-year period.

On-farm storage was fixed for Scenario A. It was capped at a maximum level of 59.4 Ml which

equates to two days of peak demand. The evolution of storage at Kings Fleet over the modelled

period is shown in Figure 12.



Figure 12: On-farm storage for the modelled period for Scenario A


Alongside storage values, annual supplied demand was generated to assess the level of

service provided to farms over the modelled period. The outputs from this are presented in

Figure 13.

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On-farm storage



Figure 13: Annual supplied demand to farms from Kings Fleet and on-farm storage


Water was also spilt from Kings Fleet during Scenario A. The annual amount of water spilt from

Kings Fleet is presented in Figure 14.

Figure 14: Annual surplus from Kings Fleet


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1970 1972 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012 2014

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Annual water volume spilled from King's Fleet



Results from this section show that there must be storage of at least 451 Ml at Kings Fleet to

meet the required LoS for farms. Key water years during the model run are 1990 and 1996

which failed to meet demand. It should be noted that if there are restrictions on water levels

within King’s Fleet or an increased environmental flow requirement from that stated in the

assumptions then the required storage would need to increase to meet the LoS. A reservoir of

the size required to meet demand is significantly larger than the current 3Ml capacity of the

Kings Fleet IDB pump sump. Consequently, a scenario with mixed storage (i.e. increasing on-

farm storage) was tested. Results from this scenario are presented in Section 4.1.2.

4.1.2 Scenario C

Scenario C was premised on variable on-farm storage at the nine delivery centres, with fixed

storage at the Kings Fleet IDB pump sump of 3 Ml (i.e. its current capacity).

There is no single solution for this scenario as the two variable parameters (on-farm storage and

pump capacity) are not independent of each other. The range of possible solutions has

therefore been plotted in Figure 15. This indicates that with increasing pump capacity the

required on-farm storage capacity reduces. The gradient of the curve increases sharply below a

pump capacity of 6 Ml/day; this indicates that the optimum balance between minimum storage

and minimum pump capacity is likely to be at this point on the curve.

Figure 15: Solutions for Scenario C (storage at on-farm reservoirs)


The parameters listed in Table 7 allow for sufficient supply to meet the minimum LoS required

by the farms (i.e. 1/20-year drought conditions) and are likely to provide the optimum balance

between pump capacity and storage.

Table 7: Parameter values for Scenario C (on-farm storage)


Kings Fleet Storage 3 Ml Current storage in the IDB pump sump

On farm storage 546 Ml Sized to meet the LoS

400

450

500

550

600

650

700

2 3 4 5 6 7 8 9 10

Tota

l On

-Fa

rm S

toa

rge

(Ml)

Pump capacity (Ml/day)

Possible Solutions for Scenario C




Pumping Capacity 6 Ml/day Sized to meet the LoS


The annual average values for inflow, supply and surplus are provided in Appendix A. Within the

45-year period, there were two years where there was a failure to meet on-farm demand. These

years were 1990 and 1996. The evolution of storage at Kings Fleet over the modelled period is

shown in Figure 16.

Figure 16: Storage at Kings Fleet IDB pump sump for the modelled period for Scenario C


In total 33017 Ml of supply was provided, with a failure to meet 268 Ml of demand over the 45-

year period. This equates to 0.80% of demand not being met over 45 years. There was a total of

112 days where supply did not meet demand over the period which equates to failure on 0.68%

of days during the 45-year period. Similar to Scenario A, there was a failure to meet supply in

the water years 1990 and 1996.

On-farm storage was varied during this model run. Figure 17 shows the evolution of on-farm

storage over the modelled period.

0.000

0.500

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1.500

2.000

2.500

3.000

3.500

1970 1972 1975 1978 1980 1983 1986 1989 1991 1994 1997 2000 2002 2005 2008 2011 2013M

egal

itre

s

Year

Storage at Kings Fleet



Figure 17: On-farm storage for Scenario C


Annual supply over the modelled period for Scenario C is presented in Figure 18.

Figure 18: Annual supply

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rage

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Annual supply to farms




Surplus water was also pumped out from Kings Fleet during Scenario C. The annual amount of

surplus water is presented in Figure 19.

Figure 19: Annual surplus from Kings Fleet


Results from this section show that if Kings Fleet were unchanged from its current state there

would need to be a minimum on-farm storage capacity of 546 Ml. Analysis of the storage

requirements at the demand centres outlined in Section 3.4 is presented in the following

section.

4.2 Delivery Centre Analysis

As part of the scope nine delivery centres were identified for Scenario C. Results of the average

annual storage at each of the delivery centres over the 45-year model period is presented in

Appendix C.

Results from this analysis show the same trends as observed in the storage values for Kings

Fleet, with less storage observed during the drought years (i.e. 1990 and 1996). It should be

noted that it was assumed that all storage at the demand centres is useable, and hence the

reservoirs could fully empty as required to service demand. Also of significance is the

assumption that all demand centres would be filled proportionally according to the percentage of

total annual demand at each delivery centre. The pipeline arrangement will require

consideration of this to ensure that the delivery centres closest to the abstraction point do not

tend to “starve” flow from those further away.

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Annual water volume spilled from Kings Fleet



4.3 Pumping Capacity

Required pumping capacity, as established during the simulation, is related to the way the

system operates and has implications on the storage needed to meet the level of service. In this

sense, it is obtained based on different constraints for the different scenarios:

● In Scenario A, the pumping rate must be able to supply the peak irrigation demand directly

from Kings Fleet. Given the existing monthly demand profile, the peak daily demand occurs

in June with a value of 6.13Ml/d. However, the considered on-site storage of 59.4Ml is able

to attenuate short term peaks in demand and therefore reduce the required pumping rate. As

a result, a pumping capacity of 5Ml/d is adequate to supply the irrigation demand directly

from the Kings Fleet.

● In Scenario C, the pumping rate must be able to transfer the required irrigation volume from

the Kings Fleet to the farms during periods of surplus to ensure water is available for the

farms during periods of high demand. Figure 20 presents the flow duration curve of the

inflow to Kings Fleet. This indicates that to meet a demand of 740Ml, flows up to around

5.5Ml/d must be abstracted so that the area below that amount and the FDC equals that

volume. In fact, that abstraction rate should be a little higher to account for periods when it is

not possible to abstract (as all storage is full) and for dry years (when a higher pumping rate

is required during periods of surplus water to take advantage of high flows during that

period). If very little storage were to be provided at King’s Fleet (as is assumed in Scenario

C) then the required pumping rate would be equal to the required abstraction rate discussed

above. As a result a pumping capacity of 6Ml/d is required for Scenario C

Figure 20: Flow duration curve for discharge to the Kings Fleet

As a result of this, the pumping capacity required in Scenario A is lower than in Scenario C.

However, it should be noted that the use of a monthly demand profile may be an additional

factor causing the pumping capacity under Scenario A to be lower than Scenario C. If a weekly

profile were available, it would probably have a higher weekly peak demand than the monthly



peak currently modelled. This would result in a higher pumping rate being required to be able to

supply the irrigation demand from Kings Fleet once the limited on-farm storage was used.

4.4 Pumping Operation

An important engineering aspect of the proposed project which is dictated by the water balance

model is the frequency that pumps are operated within the system. As part of this report

analysis was completed to determine the frequency pumps were operated under each scenario.

For Scenario A pumps were operated on 67% of the days during the model period,

corresponding to the irrigation season. This is a significant difference to Scenario C which is

presented later in this section. Pump operation was relatively uniform across the model period

except for the drought years (1990 and 1996) where it would be expected that less water is

available for pumping. Specifically, the annual minimum number of days the pump was in

operation over the model period was 244 and the maximum number of days was 253. The total

annual volume pumped under Scenario A is presented in Figure 21.

Figure 21: Total volume pumped each year for the model period under Scenario A


For Scenario A the pumps operate at design capacity on 26% of the days during the model

period and do not operate at all on 33% of the days. For the remaining 41% of the time the

pumps operate below the design capacity either because there is insufficient flow to abstract or

insufficient remaining on-farm storage capacity. Figure 22 shows the pumping rate histogram for

Scenario A. This indicates that it will be necessary to pump a wide range of daily volumes. This

will need consideration during the design of the pumping station, and will require use of the

assumed 1Ml pump balancing storage to allow the pumps to operate at design capacity for

defined periods.



Figure 22: Pumping rate histogram – Scenario A


For Scenario C the pumps are in operation on 88% of the days during the model period.

Compared to Scenario A, this is a significant increase. This would be expected as the majority

of storage is located at the on-farm storage reservoirs as opposed to Kings Fleet meaning that

water needs to be conveyed more frequently with Scenario C. During drought years such as

1990 and 1996 the pumps are observed to operate on every day of the water year, but the

pumps volume is significantly less than other years; indicating that the daily pumped volume is

somewhat below the design pump rate (and limited by inflows available for abstraction). The

number of days on which pumps operate across the 45-year period is consistently higher

compared to Scenario A. Results from the pump operation analysis for Scenario A are

presented in Figure 23 and Figure 24.

0.0%

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35.0%

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Volume pumped per day (Ml/day)

Pumping Rate Histogram - Scenario A



Figure 23: Total volume pumped each year for the model period under Scenario C


Figure 24: Number of days per year that pumps are operated under Scenario C


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Number of days per year that pumps are operated for Scenario C



For Scenario C the pumps operate at design capacity on 10% of the days during the model

period and do not operate at all on 12% of the days. For the remaining 78% of the time the

pumps operate below the design capacity either because there is insufficient flow to abstract or

insufficient remaining on-farm storage capacity. Figure 25 shows the pumping rate histogram for

Scenario C. This indicates that it will be necessary to pump a wide range of daily volumes. This

will need consideration during the design of the pumping station, and will require use of the

assumed 1Ml pump balancing storage to allow the pumps to operate at design capacity for

defined periods.

Figure 25: Pumping rate histogram – Scenario C


4.5 Resilience of the system

Results from this chapter demonstrate that a significant increase to the current storage capacity

of Kings Fleet would be required to meet farm demand in the area based on the 45-year

simulated data series. It should be noted that the storage arrangements discussed in Sections

4.1.1 and 4.1.2 are resilient to a 1/20-year event excluding climate change.

Overall, both scenarios failed to entirely meet demand for the calendar years 1991 and 1997.

The largest deficit was in 1997 with demand exceeding supply by 143Ml for Scenario A and

152Ml for Scenario C. Despite storage at Kings Fleet being zero for a longer period during

Scenario A compared to Scenario C, supplied demand is similar as the shortfall for Scenario A

was met by on-farm storage. This is reflected in Figure 26 and Figure 27 which have zero

storage at Kings Fleet for the preceding years to 1991 and 1997. During these years, demand

was met by on-farm storage.

Further analysis of storage at Kings Fleet for Scenario A and on-farm demand centres for

Scenario C is presented in Figure 26 to Figure 29. It should be noted that the results in this

section are presented in calendar years. The key to both failure years is that the storage was

0.0%

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Volume pumped per day (Ml/day)

Pumping rate histogram - Scenario C



well short of refilling during the preceding winter. It appears that failure is not caused by a dry

summer on its own, but by dry conditions over an extended period of up to 18 months.

Figure 26: Evolution of Kings Fleet Storage during 1990 and 1991 for Scenario A (calendar year)




Figure 27: Evolution of Kings Fleet Storage during 1996 and 1997 for Scenario A (calendar year)


Figure 28: Evolution of on-farm storage from 1990 to 1991 for Scenario C (calendar year)


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Evolution of on-farm storage from 1990 to 1991 for Scenario C



Figure 29: Evolution of on-farm storage from 1996 to 1997 for Scenario C (calendar year)


It is considered that the storage values generated using the model for Scenario A and Scenario

C are minimum requirements and greater storage could be added to the system to make it

resilient to the drought events simulated by the model for the water years 1990 and 1996. If the

system were to be resilient to these events storage would need to increase at Kings Fleet for

Scenario A from 451Ml to 594Ml. For Scenario C, on-farm storage would need to increase from

546Ml to 697Ml.

4.6 Optimisation of storage volume and pumping capacity

Analysis of the required storage and pump capacity for Scenarios A and C indicates that a

greater total storage and pump capacity are required for Scenario C compared to Scenario A.

This is because with minimal storage at the abstraction point (3Ml) high inflows cannot be

significantly attenuated, resulting in:

● a higher pumping rate to capture high flows

● lower overall water availability since a greater proportion of high flows are spilled into the

Deben (resulting in greater storage being required to maintain the system resilience)

A study has been carried out to investigate how increasing storage at King’s Fleet can result in

lower total storage and pump capacity requirements. The range of possible storage and

pumping capacity solutions has been plotted for a series of increasing storage amounts at

King’s Fleet (refer to Figure 30). This clearly shows that the provision of additional storage at

King’s Fleet would allow the required total storage and pump capacity to be reduced.

0

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Evolution of on-farm storage from 1996 to 1997 for Scenario C



Figure 30: Variation in total storage required according to pump capacity and storage at King's Fleet


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Tota

l sto

rage

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l)

Pump capacity (Ml/day)

Variation in total storage required according to pump capacity and storage at King's Fleet

2 Ml 3 Ml 12 Ml 25 Ml 50 Ml 100 Ml



5 Conclusions

5.1 Results and conclusions

Results from this report show that there are many inputs when attempting to derive the

minimum storage requirements for the Kings Fleet system. The quality of these inputs inevitably

influences the results produced by the model developed for this report. The simulated inflow

series provided for this study has been used as a basis for a water balance model which has

yielded results for Scenario A and Scenario C. Results from the model runs indicate a minimum

total storage between the two locations of 510Ml (Scenario A) to 550Ml (Scenario C) and a

pumping capacity between 5Ml/d (Scenario A) and 6Ml/d (Scenario C). Both options require a

similar total storage capacity and pumping capacity; therefore there is no significant

differentiator between the two options on these factors alone. The practicality and costs of the

two options will therefore be assessed further to define the preferred approach.

It is important to consider the assumptions outlined in Section 3.2 when considering the storage

requirements. It should be noted that if further data for environmental flow or minimum storage

becomes available this can be incorporated into the model. Further to this, allowances could be

added into the model to allow for climate change.

5.2 Recommendations

Based on findings from this report it is recommended that actions are taken to ensure the water

resources available for the Kings Fleet system are adequately represented within the model. It

would be useful if further information was provided for the simulated series so a greater level of

analysis can be completed. This would provide a greater level of confidence in the model

outputs.

Another key factor influencing the model was the demand profile. Currently monthly demand

values are available. As stated in Section 3.2 the demand values have a significant impact on

pumping capacity. This would need to be considered when finalising engineering options for the

scheme.

It will also be important to confirm minimum storage requirements for Kings Fleet and the on-

farm demand centres as it is currently assumed that they can be emptied (i.e. no dead storage).

Salinity is another potential issue that must be considered given the location of Kings Fleet and

the trend of EC readings taken at the IDB pump trash screen. Further investigation is required to

determine whether the measures proposed by the project subgroup will adequately control

salinity, and the frequency at which it is expected that an automatic cut out based on EC levels

would operate. In addition, consideration must be given as to whether changes in the

operation of the King’s Fleet as part of this abstraction scheme could impact on the observed

EC levels; any connectivity to groundwater should be determined and impacts of sea level rise

should be considered within this analysis.

Finally, analysis should be completed on the 1991 and 1997 drought years (calendar) to

determine the probability of their occurrence in the future when accounting for climate change. If

the probability of these events remains at 1/20-year return period than the model would

sufficiently meet the minimum LoS required by the farmers. However, if as would be expected,



drought years such as 1991 and 1997 were to increase in frequency the model would have to

be adapted to reflect this reality. The impact of climate change on the demand values should

also be considered as demand is likely to increase if summers become warmer and/or drier.



Appendices

A. Background material on the inflow series 38

B. Annual average inflow, supply and surplus 39

C. Demand centre analysis (Scenario C) 42

D. Delivery point location plan 47



A. Background material on the inflow series

Kings Fleet & Falkenham IDB Abstraction

Licence Application Yield Assessment

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29/01/2016 00:00 03/02/2016 00:00 08/02/2016 00:00 13/02/2016 00:00 18/02/2016 00:00

Conjunctive use or Farm

reservoir – yield Dependent

Current Constraints

• Estimated average yield 1500-2000Ml.

• 600-800 Ml demand for irrigation

• 1000Ml+ demand for P.W.S

• 188 Ml currently licenced

• Design year yield unknown

• Lack of local reliable flow data

• Currently two pumping stations Kings fleet and Falkenham

• Possible to move water from Kings Fleet to Falkenham

• Water Quality constraints

• Freshwater flow to Estuary

Assessing Yield

Hydrological models

Catchment Hydrology

• Available Methods include Low Flows Enterprise; NEAC model ; Catchment comparison; Rainfall run off modelling .

• Catchmod Rainfall runoff modelmost suited to this application .

• Catchment divided into hydrological zones.

• Water moves vertically through a series of conceptual stores in each zone

• Inputs Potential Evaporation and Rainfall 1970-2015.

• Calibrated with catchment observed flow data

Kings Fleet – Falkenham model Build

Inputs

• Potential Evaporation MORECS weekly .

• 1970-2015 Rainfall Locally gauged for Calibration – Levington for P.O.R. (inc other gauges for infilling).

• Flows – gauged at Falkenham and kings fleet Pumps . Check with other gauges , Holesley, Brantham, Playford etc.

• Hydrological zones; superficial Aquifer 35%, Alluvium 32%, London clay 25%, Hard surface rapid 8%

• Single unit calibration

IDB Pump data

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1000

1200

01/01/2016 00:0006/01/2016 00:0011/01/2016 00:0016/01/2016 00:0021/01/2016 00:0026/01/2016 00:0031/01/2016 00:0005/02/2016 00:0010/02/2016 00:0015/02/2016 00:0020/02/2016 00:00

Kings fleet hourly Discharge 01/01/2016 to 11/03/2015

Series1

168 per. Mov. Avg. (Series1)

24 per. Mov. Avg. (Series1)

• Significant periodicity @ 24 hour and 7 day – not hydrological – cost minimisation

• Correction required for calibration . Maximum period of 7 day selected as filter .

• Model output's reported to 7 day rolling output .

• Uncertainty regarding the more rapid response functions of the catchment .

• Local gauge and model checks indicate good accuracy of gauged data (next slide)

IDB Gauging Plausibility checks

0

50

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350

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450

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15/07/2015 03/09/2015 23/10/2015 12/12/2015 31/01/2016 21/03/2016 10/05/2016

run

off

mm

Kings Fleet & Falkenham IDB pumped cumulative runoff compared to L.F.E. Mean monthly runoff. Data shown for Time period September 2015 to March 2016 - 96 % L.T.A. Rainfall

L.F.E gauged

L.T.A. Rainfall 2015/2016 Rainfall

Series5 Poly. (L.F.E)

Poly. (L.T.A. Rainfall) Poly. (2015/2016 Rainfall)

• Early monitoring data Sep 2015 –Mar 2016 run off compared to gauge and existing steady state models .

• Sep 2015 – Mar 2016 Rainfall 96 % of L.T.A.

• Sep 2015 – Mar 2016 Measured run off 99 % L.T.A compared to L.F. E model . (95mm)

• Very encouraging checks for accurate metering .

IDB Pump Totals 2015-2016

0

200000

400000

600000

800000

1000000

1200000

1400000

1600000

1800000

2000000

CU

BIC

ME

TR

ES

Cumulative Pumped Volume

Kings fleet Falkenham 2 Falkenham 1

• Total Measured

discharge 01/08/2015 to

31/06/2016. Approx.

2800000m3

• Runoff 57 % Kings fleet:

43% Falkenham

• Area 61% king fleet: 39%

Falkenham

• Rainfall Aug to June 114

% L.T.A.

Catchmod Rainfall runoff model Calibration

• Calibrate to individual

hydrological zones .

• Soil moisture profiles

• Flow statistics including flow

duration curves .

• Catchment yield.

• Total flow

0

20

40

60

80

100

120

140

160

180

2000.00

0.05

0.10

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0.25

0.30

Rain

fall

(m

m)

Flo

w (

cu

mecs)

Date

Contribution to Flows by Area (Kings fleet)

Observed Rainfall Simulated

Area 1: Gravel crag Area 2: Alluvium Area 3: London clay

Area 4: Urban 8 per. Mov. Avg. (Observed) 7 per. Mov. Avg. (Simulated)

Total flow Calibration

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100

120

140

160

180

2000.00

0.10

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0.90

1.00

Rain

fall (

mm

)

Flo

w (

cu

mecs)

Date

Model Fit (Kings Fleet & Falkenham)

Observed Rainfall Simulated Flow 7 per. Mov. Avg. (Observed ) 7 per. Mov. Avg. (Simulated Flow)

• 7 day rolling output to remove

periodicity.

• Removes probable urban

peaks- attenuated by storage

• Good calibration of observed

aquifer baseflow trends.

• Probable 10-15 %

underestimate of long term

average yield

• Underestimate associated with

run off from marsh area , too

high S.M.D. in shoulder months.

?

•

Catchmod calibration ‘v’ existing models. L..F E

0.004

0.003 0.003

0.0020.002

0.002

0.003

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0.007

0.007

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0.005

APR MAY JUN JUL AUG SEP OCT NOV DEC JAN FEB MAR

Modelled Run off M3/s/km2 - L.F.E. and Catchmod

Catchmod Low Flows Enterprise

• Good calibration of seasonal

runoff with steady state

models .

• Baseflow months Consistently

10-15 % lower . Runoff

dominated months 10-15 5

higher.

• Consistent with

conceptualisation that L. f. E.

model overestimates baseflow

index @ 0.82 .

Calibration flow Duration statistics

0.000

0.050

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0.150

0.200

0.250

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0.350

0.400

0.000 10.000 20.000 30.000 40.000 50.000 60.000 70.000 80.000 90.000 100.000

m3

/se

c

Percentile

Catchmod and L.F.E. Mean Daily flow Duration curves

Modelled 1973-2015

L.F.E

model calibration 7 day

IDB gauged 7day

• Good Calibration with

observed

• Modelled and observed flow

expected to exceed L.T.A.

• Monitoring period generated

significantly more run off than

Long term 1970-2014 modelled

• Long term modelled conforms

to conceptualisation of

greater runoff and lower

baseflow relative to existing

model .

• Catchmod Modelled mean

yield believed to be 10-15 %

below actual .

Catchmod Aquifer zone Calibration

5.9

6.4

6.9

7.4

7.9

8.4

8.9

9.4

9.9

0.000

0.020

0.040

0.060

0.080

0.100

0.120

0.140

18/02/1982 11/08/1987 31/01/1993 24/07/1998 14/01/2004 06/07/2009 27/12/2014 18/06/2020

Gro

un

dw

ate

r Le

ve

l M

ao

d

mo

de

lle

d f

low

m3

/se

c

Axis Title

Catchmod Calibration - Aquifer flows and Observed groundwater hydrographs

Gravel sim flows elm cottage levels

Mill lane Boyton

• Aquifer 35 % of total runoff. Major summer component .

• Longer term Calibration with local groundwater levels , extends calibration period beyond flow monitoring .

• Very good trend calibration with Elm Cottage Hollesley and mill Lane Boyton.

•

Catchmod Final Calibration

0.000

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4

m3

/se

c

Kings Fleet modelled Total flow and Crag/gravel Baseflow

• Mean Daily flow data sets 1970-2015 ( calibrated to weekly)

• Winter run off more significant than other models B.F.I. 0.62 ‘v’ 0.85 L.F.E

• Vulnerability to dry winters

• Significant hard surface runoff component.

• Crag/gravel baseflow providing significant summer yield . Model believed to underestimate crag flows in dry years . Q(bf) mean = 0.025m3/sec . Probable 0.030m3/sec

• Calibration Mean run off - low 119mm, MORECS/HOST gridded 127mm (baseflow component)

IDB pumped Catchment Design Year

• IDB estimated mean

yield 2000 Ml

• Modelled mean yield

1930 Ml

• Lowest 661Ml in 1990

• Highest 5141 Ml in 2000

24

81

25

51

97

8

86

6

20

50

13

65

23

54

12

85

19

09

15

50

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91 1

83

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14

47 16

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21

99

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41

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53

46

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02

10

35

73

2 87

0

11

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02 2

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11

35

66

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14

22

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63

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41

27

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22

91

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47

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36

16

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3

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15

IDB POTENTIAL GROSS YIELD KINGS FLEET & FALKENHAM

Modelled gross yield

Catchmod Mean Gross yield

IDB Estimated Mean yield

Scheme Reliability

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1000

2000

3000

4000

5000

6000

0.0 20.0 40.0 60.0 80.0 100.0 120.0

Po

ten

tia

l y

ield

Ml

% Probability Of Available yield

Yield /Probability Curve - 1970-2015

Irrigation Only Scheme Multi use Scheme

• Assuming Resource can be

fully optimised. Unrestricted

infrastructure capability

• Multi use Scheme – 2100 Ml- 65

% chance of non-availability

in any year.

• Irrigation Scheme – 800 Ml - 4

% risk of non- availability.

• Irrigation Scheme – 600 Ml –

100 % reliable.

• Precautionary model

calibration Reasonable

assumption to increase dry

year yield by 10-15%

Further constraint

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m3

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c

Kings Fleet modelled Total flow and Crag/gravel Baseflow Design year 1995-1997

• Infrastructure to transfer

high flows.

• Freshwater flow to tide –

(S.P.A.) 0.6 Ml/day could

reduce deployable output

by 33%.

• Freshwater flow to tide

TRAC waterbody whole

estuary target. W.F.D.

assessment required .

• Salinity

• Access arrangements for

new point of abstraction .



B. Annual average inflow, supply and

surplus

Table Appendix B 1: Scenario A annual average inflow, supply, and surplus values.

Year Inflow (Ml/d) Supply (Ml/d) Surplus (Ml/d)

1970 4.49 2.03 3.00

1971 4.56 2.02 2.78

1972 1.82 2.03 0.11

1973 1.82 2.03 0.00

1974 4.68 2.03 2.05

1975 2.18 2.02 0.46

1976 4.57 2.03 2.39

1977 2.52 2.03 0.84

1978 3.99 2.03 1.71

1979 3.09 2.02 1.08

1980 3.40 2.03 1.23

1981 2.91 2.03 1.28

1982 3.83 2.03 1.41

1983 2.89 2.02 0.92

1984 3.92 2.03 1.92

1985 3.71 2.03 1.50

1986 5.04 2.03 2.30

1987 7.50 2.02 5.77

1988 3.17 2.03 1.87

1989 1.81 2.03 0.10

1990 1.84 1.76 0.00

1991 2.20 2.02 0.00

1992 2.22 2.03 0.38

1993 4.74 2.03 2.30

1994 4.72 2.03 2.59

1995 1.90 2.02 0.41

1996 1.52 1.63 0.00

1997 2.58 2.03 0.42

1998 2.99 2.03 0.64

1999 3.71 2.02 1.35

2000 9.88 2.03 7.26

2001 3.92 2.03 2.71

2002 4.86 2.03 2.90

2003 2.85 2.02 0.56

2004 2.46 2.03 0.93

2005 2.14 2.03 0.00

2006 4.78 2.03 2.02




2007 4.86 2.02 2.85

2008 3.62 2.03 2.37

2009 3.66 2.03 1.31

2010 2.93 2.03 1.25

2011 3.21 2.02 0.33

2012 5.79 2.03 4.31

2013 6.18 2.03 3.51

2014 5.76 2.03 4.02

Table B.2: Scenario C annual average inflow, supply, and surplus values.


1970 4.49 2.03 3.09

1971 4.56 2.02 2.82

1972 1.82 2.03 0.07

1973 1.82 2.03 0.05

1974 4.68 2.03 2.07

1975 2.18 2.02 0.48

1976 4.57 2.03 2.26

1977 2.52 2.03 0.82

1978 3.99 2.03 1.70

1979 3.09 2.02 1.17

1980 3.40 2.03 1.19

1981 2.91 2.03 1.21

1982 3.83 2.03 1.41

1983 2.89 2.02 1.05

1984 3.92 2.03 1.81

1985 3.71 2.03 1.62

1986 5.04 2.03 2.34

1987 7.50 2.02 5.64

1988 3.17 2.03 1.84

1989 1.81 2.03 0.12

1990 1.84 1.71 0.23

1991 2.20 2.02 0.17

1992 2.22 2.03 0.17

1993 4.74 2.03 2.22

1994 4.72 2.03 2.55

1995 1.90 2.02 0.43

1996 1.52 1.61 0.07

1997 2.58 2.03 0.39

1998 2.99 2.03 0.66

1999 3.71 2.02 1.39

2000 9.88 2.03 7.13




2001 3.92 2.03 2.72

2002 4.86 2.03 2.90

2003 2.85 2.02 0.68

2004 2.46 2.03 0.84

2005 2.14 2.03 0.22

2006 4.78 2.03 1.96

2007 4.86 2.02 2.76

2008 3.62 2.03 2.27

2009 3.66 2.03 1.45

2010 2.93 2.03 1.13

2011 3.21 2.02 0.65

2012 5.79 2.03 3.99

2013 6.18 2.03 3.57

2014 5.76 2.03 4.08



C. Demand centre analysis (Scenario C)

Figure C.1: Storage at Demand Centre A for the model period


0

20

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60

80

100

120

Sto

rage

(M

l)

Year

Storage at Demand Centre A



Figure C.2: Storage at Demand Centre B & C for the model period


Figure C.3: Storage at Demand Centre E for the model period


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Storage at Demand Centre B & C

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Storage at Demand Centre E



Figure C.4: Storage at Demand Centre F for the model period


Figure C.5: Storage at Demand Centre G&N for the model period


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Storage at Demand Centre F

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Storage at Demand Centre G & N



Figure C.6: Storage at Demand Centre H for the model period


Figure C.7: Storage at Demand Centre K for the model period


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Storage at Demand Centre H

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Storage at Demand Centre K



Figure C.8: Storage at Demand Centre M for the model period


Figure C.9: Storage at Demand Centre O for the model period


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D. Delivery point location plan

!P

M

F

K

O

H

E

A

G & N

B & C

P:\Cambridge\Demeter\EVT\Projects\379642 Felixstowe Options Appraisal\GIS\379642-MMD-00-XX-GIS-Y-001-DeliveryCentres.mxd

Rev Date Drawn Description Ch'k'd App'dMott MacDonald House8-10 Sydenham RoadCroydon, CR0 2EEUnited KingdomT +44 (0)20 8774 2000F +44 (0)20 8681 5706W mottmac.com

Suffolk Holistic WaterManagement Project

Felixstowe Option AppraisalDelivery Centres

Client

Title

DesignedDrawnGIS Check

Eng CheckCoordinationApproved

Scale at A3 Status Rev SecurityPRE P1 STD1:30,000

Notes

Key to Symbols

Location Map

Drawing Number379642-MMD-00-XX-GIS-Y-0001

© Mott MacDonald Ltd.This document is issued for the party which commissioned it and for specific purposes connected with the captioned project only. It should not be relied upon by any other party or used for any other purpose.We accept no responsibility for the consequences of this document being relied upon by any other party, or being used for any other purpose, or containing any error or omission which is due to an error or omission in data supplied to us by other parties. 0 200 400 600

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Felixstowe Peninsula Project - Green Suffolk · IP1 2BX Felixstowe Peninsula Project Concept Report...

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