{"id":298,"date":"2013-02-03T11:51:00","date_gmt":"2013-02-03T11:51:00","guid":{"rendered":"http:\/\/projectbaseline.nl\/2013\/02\/03\/2013-02-03-0954-hbos-viz-test-big-secchi\/"},"modified":"2025-08-17T13:39:44","modified_gmt":"2025-08-17T12:39:44","slug":"2013-02-03-0954-hbos-viz-test-big-secchi","status":"publish","type":"post","link":"https:\/\/projectbaseline.nl\/?p=298","title":{"rendered":"2013-02-03 09:54 hbos Viz test big Secchi"},"content":{"rendered":"

<\/p>\n

Weather : Clouded \/ SW wind 5<\/span><\/span> bft \/ Rain 0 mm \/ 1014<\/span>.7 <\/span>hpa<\/span><\/div>\n

Divers : John, Patrick, Koos, Kacper, Axel,<\/span><\/span><\/span><\/span><\/span><\/span><\/span>
Goal : Visibility test Secchi 20 cm horizontal and vertical verus 10 Secchi and Dutchi \/  SETL check<\/span><\/span>
Max depth : 16.1 mtr<\/span><\/span>
Duration : 41 <\/span>minutes<\/span><\/span>
Air temp : 5.0 celsius<\/span><\/span>
Water temp : 4,6 celsius minimum<\/span><\/span>
Fish: > 2 Perch<\/span><\/span>
Dutchi visibility: 3 mtr depth -> 8 meters.<\/span><\/span>
Secchi visibility:  3 meter depth -> 11,5 mtr<\/span><\/span>
Plants: Elodea only found in scattered small bushes at 10 mtr and deeper.<\/span>
Comment: Mussels at 3 meters and 6 meter now dislodged from measurement pile. <\/span>
A lot of copepods are swimming in the watercolumn from surface to 16 mtr depth.<\/span>
Visibility is amazing you can see the slopes at the bottom. <\/span><\/p>\n

SETL H136 Start 27-09-12 (grows very small mussels on it which are now bigger than the ones I had found on H135.<\/span>
SETL H106 Start 15-12-12 has some brown patches (diatoms) on it.<\/span>
AT both plates many shrimp use it as a savehaven.<\/span>
<\/span>
Secchi disk 20 cm <\/strong> <\/span>
Vertical from surface using divemask. = 11,5 mtr<\/span>
Horizontal at 3 mtr depth                   = 11,5 mtr<\/span>
Horizontal at 6 mtr depth                   = 11,5 mtr<\/span><\/span><\/span>
Secchi plate test 10 cm <\/strong><\/span>
<\/span>Vertical from surface not possible       = n\/a<\/span>
Horizontal at 3 mtr depth                   = 11,5 mtr<\/span>
Horizontal at 6 mtr depth                   = 11,5 mtr<\/span><\/span>
Dutchi plate test<\/strong><\/span>
<\/span>Vertical from surface not possible <\/span>
Horizontal at 3 mtr depth                   = 8 mtr<\/span>
Horizontal at 6 mtr depth                   = 8 mtr<\/span><\/span>
Conclusion  from this one-off test is that regardless the size both Secchi disk and plate give the same readings.<\/span>
There is no difference between horizontal and vertical reading when using divemask at surface. There will be a significant difference when you do not have a waterscope or divemask. Reflections \/ glare and waves at the watersurface have a negative affect on the reading.<\/span><\/p>\n

<\/a><\/div>\n","protected":false},"excerpt":{"rendered":"

Weather : Clouded \/ SW wind 5 bft \/ Rain 0 mm \/ 1014.7 hpa Divers : John, Patrick, Koos, Kacper, Axel,Goal : Visibility test Secchi 20 cm horizontal and vertical verus 10 Secchi and Dutchi \/  SETL checkMax depth : 16.1 mtrDuration : 41 minutesAir temp : 5.0 celsiusWater temp : 4,6 celsius minimumFish: > 2 PerchDutchi visibility: 3 mtr depth … <\/p>\n

Lees verder “2013-02-03 09:54 hbos Viz test big Secchi”<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"class_list":["post-298","post","type-post","status-publish","format-standard","hentry","category-hbos"],"_links":{"self":[{"href":"https:\/\/projectbaseline.nl\/index.php?rest_route=\/wp\/v2\/posts\/298","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/projectbaseline.nl\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/projectbaseline.nl\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/projectbaseline.nl\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/projectbaseline.nl\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=298"}],"version-history":[{"count":1,"href":"https:\/\/projectbaseline.nl\/index.php?rest_route=\/wp\/v2\/posts\/298\/revisions"}],"predecessor-version":[{"id":5167,"href":"https:\/\/projectbaseline.nl\/index.php?rest_route=\/wp\/v2\/posts\/298\/revisions\/5167"}],"wp:attachment":[{"href":"https:\/\/projectbaseline.nl\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=298"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/projectbaseline.nl\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=298"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/projectbaseline.nl\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=298"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}