<p>In recent years, there has been an increasing number of studies about freshwater micro-litter&#160; and how it ends up in the ocean.&#160;Nevertheless, macro-litter studies are not common in freshwater landscapes and yet less frequent among rivers. Almost always, research is focused on estuaries rather than rivers.</p><p>The Asociaci&#243;n Paisaje Limpio has been developed, for some years, several studies as an affordable methodology to measure macro-litter in rivers throughout its.</p><p>This way, our methodology is a combination between research and action. We don&#8217;t just tackle the macro-litter data field, but also identify specific litter problems along the river. We act through campaigns, agreement for companies and public administrations, etc.</p><p>A need have been observed to combined different types of methodology to monitoring different types of rivers in order to be able to draw a conclusion:</p><ul><li><strong>Visual counting</strong>: counting floating macro-litter on <strong>surface&#160;</strong>using RIMMEL app.</li>
<li>By the <strong>riverbank,</strong>through a <strong>Citizen Science</strong> tool create by Asociaci&#243;n Paisaje Limpio and Asociaci&#243;n Vertidos Cero, called <strong>eLitter</strong>. Elitter&#160;is harmonized with other marine-litter methodologies (Marine litter watch, MARNOBA in Spain) and its litter classification is based on OSPAR protocol.</li>
<li>If the <strong>riverbed&#160;</strong>is accessible eLitter is also used, but when is not accessible a dredge "Van Veen" have been used instead. This method has been applied in other marine-litter projects on seabed.</li>
<li><strong>Floating booms</strong>: it lets us know plastics rate in captured floating litter, and the water flow extrapolation.</li>
<li><strong>Nets from a kayak</strong>: to study the plastic concentration&#160; in <strong>the water column&#160;</strong>and the water flow extrapolation.</li>
<li><strong>Water quality general analysis:</strong>this analysis is useful to support the hypothesis about litter&#8217;s source in a river, mainly where the source is the sewage as happens with wet wipes, ear sticks...</li>
</ul><p>-<strong>Case study</strong>: river Lagares, a spanish river in Pontevedra, Galicia.&#160;The river Lagares flows into the Atlantic, in a Special Protection Area (SPA), a designation under the European Union Directive on the Conservation of Wild Birds.</p><p>The Asociaci&#243;n Paisaje Limpio is working on this river since 2018. We have applied the different methodologies explained before, in the river Lagares.</p>
Circulation Characteristic Analysis of Implied Water Flow Based on a Complex Network: A Case Study for Beijing, China