Braithe Estuary Partnership · Water quality programme

# Monitoring stations: schedule and sampling intervals

# Water quality programme · Schedule current at 1 February 2026

The schedule below lists the fixed stations sampled under the water quality programme. Stations are visited in
the order shown wherever the tide allows. Depths are metres below lowest astronomical tide as recorded at
installation, and are not corrected for later change.

# The programme

The water quality programme has run in its present form since 2011, when the first two stations were established
at Vardenne Quay and Thrimby Point. There are now twenty-two, the most recent added in November 2025. The
programme provides the baseline against which any change at Kellow Sands is measured, and it is the only
continuous record of salinity in the upper estuary. Sampling is carried out by the Partnership's own staff, with the
Vellamy Society providing cover during August.

Analysis is carried out under contract by Kirkhollow Analytical Laboratories. The determinations are those set by
the 2015 programme review: suspended solids, chloride, ammoniacal nitrogen, oxidised nitrogen,
orthophosphate and dissolved organic carbon, with particle size on the intertidal stations twice a year.

# Sampling

Samples are taken from a boat at the deep stations and by wading at the intertidal ones, in each case on the ebb
and within two hours of high water. Where a station cannot be reached on the day it is due it is taken as soon
afterwards as conditions allow, and the actual date is recorded: the schedule is a plan and not a record. Stations
on a weekly interval are the exception, and a missed week there is reported to the Board.

Field measurements of temperature and dissolved oxygen are taken at every visit, entered in the field book, and
transcribed into the station record within the week. Bottles are delivered to Braithe Road the same day wherever
the round permits, and are held in the refrigerated drop box overnight when it does not.

# The stations

Grid references are to the nearest ten metres and describe the position of the marker, not of the sampling point,
which at the intertidal stations is up to five metres seaward of it. Two stations are sampled quarterly rather than
monthly; both were added to answer a particular question about the southern creeks, and both are due for
review in 2027.

Access is by public footpath at every station except Marnhead Deep and Tarbert Jetty, both of which need the
harbour master's permission and a crew of two. The Partnership's insurance covers wading only where a second
person is on the shore, and staff are asked not to work the intertidal stations single-handed even where the
access itself is straightforward.

# Reporting

Results are entered in the station record within a week of the report arriving from the laboratory, and the record
is closed for the quarter at the end of the following month. A late result is entered with the date it arrived as well
as the date of sampling, because the two have diverged by as much as five weeks where the laboratory has had to
repeat a batch.

The quarterly summary goes to the Board and to the Harbour Board, and an annual summary is published.
Neither includes the field measurements, which are held in the station record and are available to anyone who
asks the secretariat for them.

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Braithe Estuary Partnership · Water quality programme

# Changes to the schedule

A station is added or withdrawn only by a decision of the Board, on a recommendation from the secretariat, and
the reason is minuted. The programme has lost three stations since 2011: two at the head of Kellow Creek, which
dried out after the storms of 2014, and one at the bar, which could not be reached safely often enough to be
worth keeping.

A change to a sampling interval does not need a Board decision and is made by the secretariat where the tide or

| Station | Grid reference | Depth (m) | Sampling interval | Installed |
| --- | --- | --- | --- | --- |
| Vardenne Quay | NX 4118 6602 | 2.4 | Fortnightly | March 2011 |
| Thrimby Point | NX 4276 6491 | 1.8 | Fortnightly | March 2011 |
| Kellow Sands north | NX 4390 6588 | 0.9 | Monthly | June 2013 |
| Kellow Sands south | NX 4402 6531 | 1.1 | Monthly | June 2013 |
| Marnhead Deep | NX 4025 6714 | 8.6 | Monthly | October 2014 |
| Braithe Bridge | NX 3982 6853 | 3.2 | Weekly | April 2015 |
| Harrowby Reach | NX 4147 6770 | 4.5 | Fortnightly | April 2015 |
| Sandiman Bank | NX 4233 6685 | 1.3 | Monthly | September 2016 |
| Vellamy Creek | NX 4318 6438 | 0.6 | Monthly | September 2016 |
| Tarbert Jetty | NX 4064 6552 | 2.9 | Fortnightly | May 2018 |
| Croyde Gut | NX 4351 6367 | 1.6 | Quarterly | May 2018 |
| Prosser Flats | NX 4189 6304 | 0.7 | Quarterly | August 2020 |
| Old Lifeboat House | NX 4295 6620 | 1.9 | Fortnightly | August 2020 |
| Training Wall east | NX 4126 6459 | 5.4 | Weekly | February 2023 |
| Lissamer Point | NX 4208 6742 | 3.7 | Monthly | February 2023 |
| Kellow Creek head | NX 4436 6612 | 0.4 | Quarterly | March 2024 |
| Vardenne Outfall | NX 4102 6571 | 2.1 | Weekly | March 2024 |
| Marnhead Bar | NX 3968 6741 | 9.3 | Monthly | September 2024 |


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Braithe Estuary Partnership · Water quality programme

Table 1 (continued)

| Station | Grid reference | Depth (m) | Sampling interval | Installed |
| --- | --- | --- | --- | --- |
| Thrimby Spit | NX 4301 6467 | 1.4 | Fortnightly | September 2024 |
| Harrowby Cut | NX 4163 6799 | 5.8 | Monthly | April 2025 |
| Boatyard Steps | NX 4088 6588 | 1.2 | Fortnightly | April 2025 |
| Cavenshaw Bight | NX 4372 6521 | 2.6 | Quarterly | November 2025 |

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