Estuaries (1130)

Habitat 1130 is generally defined as “a lower part of the river limited by brackish water and subjected to tides influence” (Warzocha 2004). In the Polish environmental conditions it refers to “river mouth”. It is an estuary section of lower part of the river flowing into the sea, limited from the landside by backwater caused by flood storm (Bajkiewicz-Grabowska and Mikulski 1993). From the seaside, the border is the outline of the outermost morphological elements of the delta built with the material transported by the river (sandbars, shoals). In the absence of morphological forms built by the river, seaward border is an imaginary line, which is a straight line connecting points of the multi-annual average of contour line "0" of the sea shore, which are located on both sides of the river mouth. In the case of estuary river sections, in which the interaction of marine waters outreach the river bed, an area of the habitat should be enlarged by the adjacent areas. It is in accordance with the definition of habitat 1130 range presented in Interpretation Manual of European Union Habitats (Michałek and Kruk-Dowgiałło 2014).

In Poland, the most complex estuaries are formed by Odra River and Vistula River (Warzocha 2004). Generally, mouths of the rivers flowing into the sea are mostly regulated and enclosed. This applies particularly to those rivers where ports were built. These regulated watercourses include: Rega River, Parsęta River, Pork River, Słupia River, Łeba River, and most of all – Vistula River (Warzocha 2004). According to the literature, criterion of habitat 1130 is met by tributaries of:

- Vistula Lagoon: Wisła Królewiecka, Szkarpawa River, Nogat River and Elbląg River,

- Gulf of Gdańsk: Vistula Przekop and Vistula Śmiała,

- Puck Bay: Gizdepka River, Reda River with Zagórska Struga,

- the open sea waters: Piaśnica River, Łeba River, Słupia River, Wieprza River, Szczuczy Channel, Czerwona River, Rega River, Resko Channel, Liwka Channel, Parsęta River and Dziwna River.

In 2017, the Maritime Institute in Gdańsk is going to conduct environmental studies within the framework of the project ”Pilot monitoring studies of marine habitats and protected species in 2015-2018. The results will allow to assess the condition of the habitat 1130.

Literature

1. Bajkiewicz-Grabowska E., Mikulski Z. 1993. Hydrologia ogólna. Wydawnictwo Naukowe PWN, Warszawa, ISBN 8301112662.

2. Interpretation manual of European Union Habitats 2013. EUROPEAN COMMISSION DG ENVIRONMENT Nature ENV B.3, EUR 28, April 2013, 144 p.

3. Michałek M., Kruk-Dowgiałło L. (eds) 2014. Zbiorcze sprawozdanie z analizy dostępnych danych i przeprowadzonych inwentaryzacji przyrodniczych (zebranie i analiza wyników inwentaryzacji, materiałów niepublikowanych i opracowań publikowanych, przydatnych do sporządzenia projektów planów) Ostoja w Ujściu Wisły (PLH220004). Projekt rozporządzenia Ministra Środowiska ws. planu ochrony obszaru PLH220004.

4. Warzocha J. 2004. Ujścia rzek (estuaria). [in:] J. Herbich (ed.) Siedliska morskie i przybrzeżne, nadmorskie i śródlądowe solniska i wydmy. Poradniki ochrony siedlisk i gatunków Natura 2000 - podręcznik metodyczny Ministerstwo Środowiska, Warszawa, vol. 1, 31-36.