In December 2014 WRT held a Catchment Based Approach and Catchment Restoration Fund Conference in Exeter. The University of Plymouth's Sean Comber gave a summary of their work with WRT to examine the effects of road run-off on the Upper River Teign.
Perceptions and practices of rice farmers in the lowland areas of Diplahan, Z...
WRT CaBA/CRF Conference 02/12/14 - Sean Comber
1. Road run off and reasons for
failure ‐ Fingle Brook A30 study
regarding impacts on the river Teign
Sean Comber, Will Blake,
Rupert Goddard, Chris Rowett,
Alex Taylor
3. Background
• Water Framework Directive is driving higher
expectations for water quality and lower
standards
• Large areas of SW not compliant
• For a number of reasons
– P from WwTW/Agric/Industry
– Legacy mine issues
– Obstructions
– Road runoff/urban runoff
4. • Fingle Brook only moderate
status (based on fish)
• Part of The Dart and Teign River
Improvement Project (DTRIP)
• Catchment Restoration Funds
available for assisting meeting
WFD status by 2027
Teign Catchment
Fingle Brook
6. What are the pressures on Fingle
Brook?
• Sewage effluent (Whiddon Down)
• Mines (Whiddon Down - Cu some Pb;
Drewsteignton Quarry – limestone,
may be metals before that)
• Road runoff
• Agriculture
10. Metals in runoff
0.01
0.1
1
10
100
1000
0 10000 20000 30000 40000 50000
Concentration(µg/l)
Average daily traffic
Cd
Cu
Pb
Zn
A30 average 2-way daily traffic
Data from: Harrison et al., 1985, Hewitt and Rashed, 1992, Legret and Pagotto, 1999, Bäckström et al., 2003
11. Work so far
• Environment Agency cannot hope to provide detailed
monitoring on sub-catchment level
• Plymouth University working with WRT and EA to increase
knowledge base
• Student projects:
– 3rd Year dissertation (Chris Rowett – metal bioavailability in
runoff water from Whiddon Down settlement pond; Rachel
Giles - Effects of Road Salt Runoff on Freshwater Organisms –
Brighton Stream)
• Small contracts:
– Investigation of water and sediment quality relating to A30 road
runoff into Fingle Brook, upper Teign catchment, Devon (March,
2014)
– Assessing significance of sources of metals to Fingle Brook
under low and high flow conditions (July – December 2014)
13. Metals elevated above probable effect levels
(Canadian standards - mg/kg) for some metals
Variables
Freshwater
(TEL)
Freshwater
(PEL)
Fingle Brook
channel sediments
Lead 35 91.3 113
Chromium 37.3 90 184
Copper 35.7 197 38
Zinc 123 315 285
TEL = Threshold Effect Level (below which no impacts)
PEL = Probable Effect Level (above which expect negative impacts)
14. Mean metal levels in sediment (mg/kg)
SAMPLE Zn Cu Cr
ROAD DUST 756 282 183
LAGOON 785 113 176
SOIL 69 25 138
BANK 141 35 175
MAIN CHANNEL SED 285 38 184
NORTH TRIB SED (drain input) 321 65 190
NORTH TRIB SED (no drain input) 164 30 167
SOUTH TRIB SED (drain input) 212 33 172
15. Water Quality?
Metal Speciation & Toxicity
Most toxic
Intermediate
toxicity
Low toxicity
DOC
Humic
M-Org
CO3
2-
S2-
OH-
NO3
-
M+
M++
M-Inorg
Fulvics
X
EDTA
16. Water quality – New standards (EQS)
• Important to assess bioavailability (Cu, Zn, Ni,
(Mn, Pb)) – site specific
EQS available based on
measurement of Ca,
pH, dissolved organic
carbon and dissolved
metal – set by EU &UK
• Other EQS set by UK
17. Sample sites
• Sampled during
dry period
(baseline) and 2
rain events (Dec
‘13 and Jan ‘14)
18.
19. Sites number: 1 = road runoff; 2 = outlet from wetland; 3 =
inflow to river; 4 = u/s of inflow; 5 = d/s of inflow
A-D = occasions during rain event
0
2
4
6
8
10
12
14
16
18
20
22
DissolvedCuconcentration(µgl-1)
Sample location
20. Sites number: 1 = road runoff; 2 = outlet from wetland; 3 =
inflow to river; 4 = u/s of inflow; 5 = d/s of inflow
A-D = occasions during rain event
21. Sites number: 1 = road runoff; 2 = outlet from wetland; 3 =
inflow to river; 4 = u/s of inflow; 5 = d/s of inflow
A-D = occasions during rain event
0
10
20
30
40
50
60
70
80
90
100
DissolvedZnconcentration(µgl-1)
Sample location
22. Detailed water quality survey to determine sources of metals
1) Downstream of STW
2) Upstream of Widdon Down mine site
3) Input of Widdon Down mine site
4) Downstream of Widdon Down mine site
5) Upstream of Drewsteignton quarry
6) Input of Drewsteignton quarry
7) Downstream of Drewsteignton quarry
8) Upstream of Millfarm road drain
9) Input Millfarm road drain
10) Downstream Millfarm road drain
11) Upstream of Redlake road drain
12) Input of Redlake road drain
13) Downstream of Redlake road drain
14)Upstream of Lower Puddicombe road drain
15) Input of Lower Puddicombe road drain
16) Downstream of Lower Puddicombe road drain
17) Upstream of Veet Mill road drain
18) Input of Veet Mill road drain
19) Downstream of Veet Mill road drain
20) Upstream of Fingle Brook input into the River Teign
(Fingle Bridge)
21) Input of Fingle Brook into the River Teign (Fingle Bridge)
22) Downstream of Fingle Brook input into the River Teign
(Fingle Bridge)
24. Main inputs to Fingle Brook under low
flows (µg/l)
• High flow samples collected 18/11/14
Site Cu Ni Zn Co Se Cd Pb
3A Widdon Down mine site 0.63 5.10 4.4 0.52 1.85 0.02 0.2
6A Drewsteignton quarry 0.25 0.28 3.5 0.01 10.13 0.05 0.2
9A Millfarm road drain 5.34 2.57 13.2 0.17 0.17 0.02 27.1
18A Veet Mill road drain 2.05 8.84 13.2 0.62 0.17 0.12 0.6
15A Lower Puddicombe drain 2.68 8.34 17.3 3.10 0.56 0.26 5.8
12A Redlake road drain 7.56 1.79 8.6 0.11 0.34 0.03 12.4
25. Conclusions & future work
• The sewage works input is a low constant flow, with most metals
present, Zn being the most significant
• Mine water low/constant flow high Se, Co, Mn, Ni, Zn, Cd, Mo, Fe
• Road runoff sporadic but high in Zn, Pb, Cu, Mo, Cd
• Contribution from field drains seems low
• Overall metal concs are not exceptionally high, but high enough
to warrant further investigation (especially Pb)
• Wetland exhibits poor efficiency for metal removal
• Road runoff flow has obvious impacts on stream’s hydrology
(potentially greatest impact on stream ecology) – wetland needs
improving + consider others along older sections of A30
• High flow full stream survey complete, awaiting analytical results
• Combine flow data with concentrations to try an apply some
source apportionment to the key inputs