River Itchen Sustainability Study

River Itchen Sustainability Study WATER QUALITY Phase III Discussion Meeting with Watercress Growers Association Alresford 25 September 2003

Contents • Estuary stratification, ammonia, dissolved oxygen and temperature • River RE 1 in MU6 – precautions • River Phosphorus – standards, current conditions, potential problems and possible solutions

Requirements for Target Species – Water Quality Issues • RE 1 (salmon) DO - 80% saturation (10 %ile) BOD - 2.5 mg/l (90 %ile) Ammonia - 0.25 mg/l (90 %ile) • Suspended solids - 10 mg/l annual average. Also <10% silt in surface sediments (salmon) • Orthophosphate - <0.06 mg/l - annual average (eutrophication) • Other issue – endocrine disrupters?

Flow Balance â&#x20AC;&#x201C; September 1992

Designated Shellfish Water

G r a ve l s i lt a t io n E g g s / A le v in s P a rr S m o lts A d u lt s e n t e r ri ve r S p a w n i n g m i g ra t io n S p a w ni ng

Critical

Being Assessed

December

November

October

September

August

July

June

May

April

March

February

January

SALMON - Criticality of Seasonal Monthly River Flow for Key Life Stages

Water Quality Standards – Fluvial/Marine DO River GQA Grade A Freshwater Fish Directive – Salmonid Standard Estuary (proposed)

80% sat.

10%ile 9 mg/l 50%ile 6 mg/l absolute limit 80% annual average 5 mg/l 5%ile (Bedford 2003)

BOD (ATU) 5d 20°C 2.5 mg/l 90%ile

Ammonium 0.25 mg N/l 90%ile 1 mg/l 0.78 mg N/l Derogation to 3 mg NH4/l if healthy fish population 0.86 mg N/l 95%ile

Unionised ammonia

0.025 mg/l 0.02 mg N/l

0.025 mg NH3/l NH3, 0.021 mg N/l equivalent to NH4 at 15°C, 0.4 salinity (Nixon et al.

1995, Alabaster & Lloyd 1982))

Temp.

21.5 °C 98%ile

Cobden Bridge – Salinity – Neap Tide

Cobden Bridge - Temperature Temperature 25 Cobden Br.

Temperature deg. C

20

15

10

5

0 11-Aug-87

07-May-90

31-Jan-93

28-Oct-95 Time

24-Jul-98

19-Apr-01

14-Jan-04

Cobden Bridge - Ammonia Itchen Estuary - Cobden Bridge 2.5 Ammonia Linear (Ammonia)

Ammonia N mg/l

2

1.5

1

0.5

y = -0.0128x + 0.6678 R2 = 0.1004

0 0

5

10

15

20 Salinity psu

25

30

35

40

Cobden Bridge – Ammonia – Neap Tide

Model Boundary Conditions July 1994 Inputs

July 1994 model

River flow m3/s Test 9.27 Itchen 4.95 Hamble 0.42

BOD org N NH4 NO3 PO4 DO % SS Algal C

Concs.

Portswood mg/l 5 5 20 0.5 5 50 20 0

Mean tidal ranges m Spring m 4 Neap m 1.9

Itchen mg/l 2 1 0.07 5 0.3 100 15 0

Loads Portswood kg/d 130 130 518 13 130 130 518 0

River kg/d 855 428 30 2138 128 4277 6415 0

STW flow m3/s Portswood 0.3

Ratio R/STW 6.60 3.30 0.06 165.00 0.99 33.00 12.38

Portswood STW Effluent/River Mixing Portswood STW Effluent/River Mixing

2.50

Concentration mg/l

100.00

Ammonium BOD DO low DO high

95.00 90.00

2.00

85.00

1.50

80.00 75.00

1.00

70.00 0.50

65.00

0.00

60.00 0

1

2

3

4

Fluvial Discharge m3/s

5

6

7

% saturation

3.00

Cobden Bridge â&#x20AC;&#x201C; DO % sat.

Itchen Estuary - Cobden Bridge 180

Dissolved Oxygen % sat.

160 140 120 100 80 60 40 20 0 01-Jan-90

01-Jan-92

01-Jan-94

01-Jan-96

01-Jan-98

01-Jan-00

01-Jan-02

Cobden Bridge â&#x20AC;&#x201C; DO v Salinity Itchen Estuary - Cobden Bridge 180 160 140

DO % sat.

120 100

y = -0.461x + 93.001 R2 = 0.0892

80 60 40 20 0 0

5

10

15

20 Salinity psu

25

30

35

40

Cobden Bridge – DO – Neap Tide

Dissolved Oxygen â&#x20AC;&#x201C; Itchen Estuary 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0

60000 DO %

Conductivity

50000 40000 30000 20000 10000 0

Conductivity (uS/cm) .

Dissolved Oxygen (% sat)

Dissolved Oxygen, and Conductivity at Cobden Bridge - (Sept 5th - Sept 21st 2003)

Requirements for Target Species – Water Quality Issues • RE 1 (salmon) DO - 80% saturation (10 %ile) BOD - 2.5 mg/l (90 %ile) Ammonia - 0.25 mg/l (90 %ile) • Suspended solids - 10 mg/l annual average. Also <10% silt in surface sediments (salmon) • Orthophosphate - <0.06 mg/l - annual average (eutrophication) • Other issue – endocrine disrupters?

Ammonia - Gaters Mill R. Itchen, Gaters Mill 0.5 0.45 0.4

Ammonia N mg/l

0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 28/07/01 00:00

07/08/01 00:00

17/08/01 00:00

27/08/01 00:00

06/09/01 00:00 Time

16/09/01 00:00

26/09/01 00:00

06/10/01 00:00

DO Gaters Mill August 2002 Turbidity (FTU) and Dissolved Oxygen (% sat)

Turbidity, Dissolved Oxygen, and Conductivity at Gaters Mill - August 2002 120 110 100 90 80 70 60 50 40 30 20 10 0

1000 800 700 600 500 400 300 200 100 0

DO %

Turbidity

Conductivity

Conductivity (uS/cm)

900

Dissolved Oxygen - Easton 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0

1000 900 800 700 600 500 400 300 200 DO %

Conductivity

100 0

Conductivity (uS/cm) .

Dissolved Oxygen (% sat)

Dissolved Oxygen, and Conductivity at Easton - (July 31st - August 14th 2003)

Itc he n

by pa ss

Ea st on

LOCATION

Av er ag e

Ab ba Br s oo FF k, Bo ro ug h Itc Br he id n ge Na Ar vi ga le ,D tio ro n, ve G ar La ni ne er Rd Itc ,W he Ca in n ch rr ,G ie es ar ro te ni fI r e tc rR he d n, ,W Itc in he ch n es Va te lle r y Co Itc un he try n, Itc Ri Pa ve he rk rI n nn Na ,B vi ga is ho tio ps n, to u/ ke s Ch ic he nh al lS TW

Ca nd ov er

Al re sf or d

d/ s

d/ s

Itc he n

Itc he n

DO % sat.

Early Morning Dissolved Oxygen Dissolved Oxygen 0700-0800 hrs

100 90 80 70 60 50 40 30 20 10 0

14-17 July 2003

4-7 August 2003

Upper Catchment Routine Monitoring Data: Suspended Solids SS-Q Borough Bridge, Drove Lane 96-99 1.20

40

SS- BB

35

SS DL

30

Q

1.00

0.60

20 15

0.40

10

0.20

5

08/11/99

08/08/99

08/05/99

08/02/99

08/11/98

08/08/98

08/05/98

08/02/98

08/11/97

08/08/97

08/05/97

08/02/97

08/11/96

08/08/96

0.00

08/05/96

0

Q m3/s

0.80

25

08/02/96

SS mg/l

45

Watercress Farm Suspended Solids Watercress Farm Suspended Solids 100 90 A

B

C

D

E

F

I

J

Suspended Solids mg/l

80 70 60 50 40 30 20 10 0 13-Jul-02 01-Sep-02 21-Oct-02 10-Dec-02 29-Jan-03 20-Mar-03 09-May-03 28-Jun-03

Watercress Farm Zinc Watercress Farm Zinc 200 180 160

A

B

C

D

E

F

I

J

Zinc ug Zn/l

140 120 100 80 60 40 20 0 13-Jul-02 01-Sep-02 21-Oct-02 10-Dec-02 29-Jan-03 20-Mar-03 09-May-03 28-Jun-03

Watercress Farm Malathion Watercress Farm Malathion 100 90

A

B

C

D

E

F

I

J

80

Malathion ng/l

70 60 50 40 30 20 10

0 13-Jul-02 01-Sep-02 21-Oct-02 10-Dec-02 29-Jan-03 20-Mar-03 09-May-03 28-Jun-03

P (mg/l) Values Assigned to River Types Geological 1.

2. River 3. Large class Headriver waters C Natural 0.02 0.02 0.02 Standard 0.04 0.06 0.06 Threshold 0.06 0.10 0.10 E Natural 0.02 0.03 0.03 Standard 0.06 0.10 0.10 Threshold 0.10 0.20 0.20

Itchen Guideline Standards (mg/l) • • • • • •

MU1 Cheriton MU2 Arle MU3 Candover MU4 MU5 MU6

C1 C2 C1 C2 C2 E2

0.04 0.06 0.04 0.06 0.06 0.10

Phosphorus 1997-1999

P MU1 3812 MU2 3858 MU3 52/41 Total MU4 3806 MU5 3796 MU6 3786

Q m3/s 0.5 1.6 0.5 2.6 3.8 4.8 4.8

Conc. mg/l Load g/sIncr. g/s 0.037 0.019 0.083 0.133 0.033 0.017 0.065 0.168 0.063 0.239 0.07 0.120 0.576 0.34 0.370 1.776 1.20

Q and P in River Itchen Modelled Orthophosphate Concentration and Flow in River Itchen - Average Flow (Q50) Management Unit 4

Management Unit 5

Management Unit 6

7.00

0.400 Chickenhall STW Discharge

Mill House FF Discharge

0.350 Springvale WCBF Discharge

Flow (cumecs)

5.00

4.00

Harestock STW Discharge

Avington Trout FF Abstraction

Mill House FF Abstraction

Gaters Mill PWS Abstraction Otterbourne PWS Abstraction

0.300

0.250

Test Valley FF Discharge

0.200 3.00 0.150 2.00

Avington Trout FF Discharge, Test Valley FF Abstraction

0.100

1.00

0.00 7.00

0.050

9.00

11.00

13.00

15.00

17.00

19.00

21.00

23.00

25.00

27.00

29.00

31.00

33.00

35.00

Chainage (km) Calculated Flows (Q50)

Modelled Orthophosphate Concentration (C50)

P-Standard

0.000 37.00

Orthophosphate (mg/l)

6.00

P MODELLED FOR 50%ile FLOW

6.00

1.00

5.00

0.90 0.80 0.70

4.00

0.60 0.50

3.00

0.40

2.00

0.30 0.20 0.10

1.00 0.00 7.00

12.00

17.00

22.00

27.00

32.00

Orthophosphate (mg/l)

Q (cumecs)

ITCHEN

0.00 37.00

Chainage (km) Flow Orthophosphate from C against Q plot

Modelled Orthophosphate Orthophosphate from normal dist.

P Modelled for 50%ile Flow

6.00

1.00

5.00

0.90 0.80 0.70

4.00

0.60 0.50

3.00

0.40

2.00

0.30 0.20 0.10

1.00 0.00 7.00

12.00

17.00

22.00

27.00

32.00

Orthophosphate (mg/l)

Q (cumecs)

ITCHEN

0.00 37.00

Chainage (km) Flow Orthophosphate from C against Q plot

Modelled Orthophosphate Orthophosphate from normal dist.

Divert Morestead (5 mg/l) to Harestock C.4.1. Modelled P. concentration (mg/l) in R. Itchen for strategy F1 MU5

MU6

6.00

5.00

Flow (cumecs)

4.00

3.00

2.00

1.00

0.00 7.00

9.00

11.00

Flow (cumecs)

13.00

15.00

17.00

19.00

21.00

23.00

Chainage (km)

25.00

27.00

Modelled P. conc. for scenario F1 (mg/l) with scenario

29.00

31.00

33.00

35.00

0.50 0.48 0.46 0.44 0.42 0.40 0.38 0.36 0.34 0.32 0.30 0.28 0.26 0.24 0.22 0.20 0.18 0.16 0.14 0.12 0.10 0.08 0.06 0.04 0.02 0.00 37.00

Modelled P. conc for base case

Phosphorus (mg/l)

MU4

Divert Alresford (5 mg/l) to Arle Confluence C.4.2. Modelled P. concentration in R. Itchen for strategy F2 6.00

0.20 0.18 0.16 0.14

4.00

0.12 3.00

0.10 0.08

2.00

0.06 0.04

1.00

0.02 0.00 7.00

0.00 9.00 11.00 13.00 15.00 17.00 19.00 21.00 23.00 25.00 27.00 29.00 31.00 33.00 35.00 37.00

Chainage (km) Flow

Modelled P. conc. (mg/l)

Modelled P. conc. without strategy

Phosphorus (mg/l)

Flow (cumecs)

5.00

Harestock to Chickenhall â&#x20AC;&#x201C; 0.5 mg/l C.4.4. Modelled P. concentration in R. Itchen for strategy H 6.00

0.13 0.12 0.11

5.00

0.09

4.00

0.08 0.07

3.00

0.06 0.05

2.00

0.04 0.03

1.00

0.02 0.01

0.00

0.00 7

9

11

13

15

17

19

21

23

25

27

29

31

33

Chainage (km) Flow

Modelled P. conc (mg/l)

35

37

Phosphorus (mg/l)

Flow (cumecs)

0.10

River Itchen Schematic Franklyns FF

: 0.737

Pinglestone WCF : 0.088

R.CANDOVER

Manor Farm WCF : 0.189 Manor Farm FF

Fobdown WCF Upper

: 0.159

: 0.038

Beds 16-19 : 0.038 Farm Avington FF

: 0.520

Test Valley FF

: 1.319

: 0.038

Borough Br. MU3

Springvale WCF : 0.084

Drove Lane MU2

Easton MU4

Lower Bishops WCF : 0.243

Alresford By-pass MU1

Harestock STW : 0.051 Mill House FF : 0.310

Otterbourne MU5 Poles Lane Stream

Nythe WCF

R.CHERITON

Otterbourne WTW Bow Lake

Intake

: 0.347

Allington Lane Stream

West Lea WCF : 0.040 : 0.530

Discharge : 0.030 Fishers Pond FF

: 0.098

Drayton WCF : 0.150

Spring Garden WCF : 0.150

: 0.080

Morelands Cope FF : 0.010

KEY HM Victualling STW : 0.001

Discharge : 0.020

Discharge to river Abstraction from river

Gaters Mill MU6 Gaters Mill WTW Intake : 0.530

R.ITCHEN

Abstraction from and discharge to river MU4

Principal flow monitoring station for management unit 4 FF: Fish farm

WCF: Watercress farm

Notes: Flows are consented discharges/abstractions (m3/s).

STW: Sewage treatment works WTW: Water treatment works

Fish Farm Effluent Orthophosphate Fish Farm Effluent Orthophosphate 0.200 0.180

Orthophosphate mg/l

0.160 0.140 0.120 0.100 0.080 0.060 0.040 0.020 0.000 A

B

C

D

E

F

G

H

I

Q and P in River Arle Modelled Orthophosphate Concentration and Flow in River Arle - Average Flow (Q50) 2.50

0.250 Pinglestone WCBF Discharge

Franklyns FF Discharge

2.00

0.200

West Lea WCBF, Nythe WCBF, Drayton WCBF Discharge

1.50

1.00

Maxwell WCBF Discharge

0.150

Lower Bishop Sutton WCBF Discharge

Franklyns FF Abstraction

0.100

0.50

0.050

0.00 0.00

0.000 1.00

2.00

3.00

4.00

5.00

Chainage (km) Calculated Flows (Q50)

Modelled Orthophosphate Concentration (C50)

P-Standard

Orthophosphate (mg/l)

Flow (cumecs)

Manor FF Abstraction & Discharge, Manor WCBF Discharge

R. Arle, 50%ile Flow

Flow (cumecs)

2.00

0.25 0.20

1.50

0.15 1.00

0.10

0.50

0.05

0.00

0.00

0.00

1.00

2.00

3.00

4.00

Orthophosphate (mg/l)

Modelled Orthophosphate Concentration and Flow in River Arle

5.00

Chainage (km)

Calculated Flow Orthophosphate - C against Q P-Standard

Modelled Orthophosphate Orthophosphate - Normal Distribution

R. Arle, 80%ile Flow

Flow (cumecs)

2.00

0.25 0.20

1.50

0.15 1.00

0.10

0.50

0.05

0.00

0.00

0.00

1.00

2.00

Calculated Flow Orthophosphate - C against Q P-Standard

3.00 Chainage (km)

4.00

Orthophosphate (mg/l)

Modelled Orthophosphate Concentration and Flow in River Arle

5.00

Modelled Orthophosphate Orthophosphate - Normal Distribution

R. Arle, 80%ile Flow, 0.060 mg.l WF

Flow (cumecs)

2.00

0.25 0.20

1.50

0.15

1.00

0.10

0.50

0.05

0.00 0.00

0.00 1.00

2.00

Calculated Flow Orthophosphate - C against Q P-Standard

3.00 Chainage (km)

4.00

Orthophosphate (mg/l)

Modelled Orthophosphate Concentration and Flow in River Arle

5.00

Modelled Orthophosphate Orthophosphate - Normal Distribution

Watercress Farm Effluent Orthophosphate Watercress Farm Effluent Orthophosphate 0.400

Orthophosphate mg/l

0.350 0.300 0.250 0.200 0.150 0.100 0.050 0.000 A

B

C

D

E

F

G

H

I

J

K

L

Watercress Farm Effluent â&#x20AC;&#x201C; P Conc.

Watercress Farm Orphophosphate

Orthophosphate mg P/l

0.6 0.5 0.4 0.3 0.2 0.1 0

A

B

C

D

E

F

I

J

Total/Soluble Phosphorus Ratio Phosphorus Phase 0.7

Total Phosphorus mg/l

0.6

y = 1.1536x R2 = 0.7919

0.5 0.4 0.3 0.2 0.1 0 0

0.1

0.2

0.3 Orthophosphate mg/l

0.4

0.5

0.6

Watercress Farm Effluent P Concentration and Loads Watercress Farm Effluent Phosphorus

Orthophosphate 0.200

Total Phosphorus Soluble P Load

2.50

0.160 0.140

2.00

0.120 0.100

1.50

0.080 1.00

0.060 0.040

0.50

0.020 0.000

0.00 A

B

C

D

E

F

G

H

I

J

Soluble P load t/d

Orthophosphate, Total Phosphorus mg P/l

0.180

3.00

Future Work Towards RISS • More detailed water quality modelling with ISIS – (Q input data?)

• Identification of future strategies (Q/c scenarios?)

• Indication of financial implications (balance cost against ecological risk)