Tamar Estuary

Question 1

Tamar Estuary

Answer 1

Rises 6km from N Devon coast, 70km long
Main freshwaster input (-50%) to Plymouth, annual average flow is 30m3/s, occasional instantaneous flow >100m3/s
Upper, tidal mudflats and reed beds
Lower, Plymouth, dockyards, military, rocky shore

Question 2

Point sources and impacts

Answer 2

Locations of some of the larger discharge consents to Plymouth sound
- Closed symbols, sewage >356m3/d
- open symbols, trade and others >500m3/d
Additional agri inputs and point inputs fro boats that can impact phosphate concentrations.

Question 3

Estuarine mixing

Answer 3

large seasonal variability due to runoff, residence times and point source.
Nitrate shows conservative behaviour while Si shows conservative but not in summer
Phosphate non con behaviour with clear evidence of point sources.

Question 4

Summary

Answer 4

NO3 behaves conservatively in Tamar
Student data shows in summer NO3 doesn’t always show con
Phosphate behaves in a non con with large inputs from sed resuspension and point sources of sewage
Large interannual variability for both nitrate and phosphate.