Date: 1 January 2014
 

Monitoring Team: Mark, Nick & Ian
 

Analysis & Report: David Bills-Thompson, PFCG Technical Officer and Data Co-ordinator

 

Commentary: A significant result this month is the positive gain in sand height at all

reference posts. This is the first time a total gain has been recorded in 50

weeks.

 

This data is best viewed in a new chart called Height Table 0114.pdf. This is not

new data, just a clearer way of highlighting gain and loss.

 

Now that we are approaching a full season of data collection, there is

evidence of seasonal variation visible in the height table. The pattern of

colours around posts 5 and 6 suggest that this part of the beach has the

greatest potential for reliable sand gain.

 

The greatest sand gain was at post 8 and although the height has not yet

reach the level of 12 months ago, it has exceeded the level in April when the

first profile measurements where taken.

 

This dramatic performance at post 8 is another example of the instability we

can expect at this part of the beach. Sand heights at Post 8 continue to be the

lowest known points on the beach.

 

The general increase in sand height is also visible in the beach profiles

starting at posts 4 and increasing around through the higher numbered posts

where there is a noticeable gain in sand height in the deeper water, giving the

effect that the tide is going out further.

 

The Profile Post 8 0114.pdf shows a large amount of sand build up in the deeper

water. See also the other post profiles.

 

The sand height increase seems to have influenced the dune toe distance

with all except post 5 recording a reduction in dune toe distance. Post 9 has

had the largest toe reduction which also made it difficult to decide where the

toe was.

 

Another method of toe measurement using laser heights behind the post may

be required on all of the posts and not just 11 and 12 as predicted with earlier

observations.

 

The real value of beach monitoring will be apparent in another 12 months

when we are able to quantify the net annual loss of sand in various locations.

I am assuming there will be a net annual loss by comparing the data from

1996 with today.

 

Measurements of the dune crest were also taken at posts 8 and 9 along with

lateral crest positions at NS1 and NS2 (Between posts 5 & 6). This data has

not yet been evaluated.

 

While walking between posts 8 and 9 behind the dune crest, I noticed a

number of flat leafed sticky weeds that were holding a considerable amount of

sand. Surrounding weeds that were not sticky did not hold any sand. This

sand had obviously been carried there by wind so we should not discount the

amount of wind erosion that is also occurring.