| Underwater available substrate |
Greater variety and/or proportion of potential substrates provide different food and fixation resources for organisms, favoring biodiversity and ecosystem functioning. In sandy bottom streams, the entry of substrates from adjacent land areas is essential for the provision of leaves, branches, trunks, and fruits. |
Optimal |
The site presents sand, deposition of organic material, aquatic vegetation, trunks, branches, and leaves accumulating underwater, providing bottom substrates in 76% to 100% of the evaluated site. Occasional occurrence of gravel can be detected |
20-16 |
| Good |
The site presents substrate for the aquatic fauna, such as sand, trunks, branches, and leaves accumulating underwater in 51% to 75% of the evaluated site. Occasional occurrence of aquatic vegetation and deposition of organic material can be detected. |
15-11 |
| Regular |
The site presents low occurrence or absence of organic material deposition or aquatic vegetation. The presence of sand prevails, with a few occurrences of trunks, branches, and leaves in 26% to 50% of the evaluated site |
10-6 |
| Poor |
The site presents sand dominated substrates. Water flow carries substrates and limits the establishment of submerged aquatic vegetation and reduces or buried organic material previously deposited. Less than 25% of the site presents trunks, branches and leaves. |
5-0 |
|
Parameter
|
Significance
|
Quality status
|
Interpretation
|
Scoring
|
| Underwater habitat complexity |
The variety of shapes, textures, sizes and the abundance of underwater structuring increase the availability of shelter against predation and provide places for reproduction and feeding. Underwater substrate contributes to the stabilization of the sediment and favors the occurrence of distinct flow regimes. Higher environmental heterogeneity contributes to the maintenance of higher biodiversity. In the case of sandy bottom streams, the input of structuring material from the terrestrial environment is essential for underwater heterogeneity |
Optimal |
The site presents aquatic vegetation, branches and leaves underwater, marginal vegetation leaning over the stream channel, presence of backwaters, small waterfalls and excavated banks distributed along 76% to 100% of the site as potential habitats. |
20-16 |
| Good |
The proportion of potential habitats is found in 51% to 75% of the site, with branches and leaves underwater, marginal vegetation leaning over the channel, small waterfalls. Minimal occurrence or absence of aquatic vegetation, excavated margins and large backwaters. |
15-11 |
| Regular |
The site presents 25% to 50% of potential habitats, with branches and leaves underwater, marginal vegetation leaning over the channel, small waterfalls. Minimal occurrence or absence of aquatic vegetation. Few or absence of backwaters for shelter and reproduction of aquatic communities |
10-6 |
| Poor |
Aquatic vegetation, backwaters, small waterfalls and marginal vegetation leaning over the channel are absent. Minimal occurrence of trunks, branches and leaves underwaters, in less than 25% of the site |
5-0 |
|
Parameter
|
Significance
|
Quality status
|
Interpretation
|
Scoring
|
| Velocity Depth combinations |
The variety of combinations of flow and depth favors the occurrence of organisms with different ecological requirements and increases biodiversity. It also contributes to the maintenance of a balanced sediment, particles and nutrients transport and deposition dynamics. In sandy bottom streams, the accumulation of branches, trunks and leaves contributes to the creation of small dams and differentiated flow regimes |
Optimal |
Occurrence of 4 types of regimes. Fast/shallow, fast/deep, slow/shallow; slow/deep |
20-16 |
| Good |
Occurrence of 3 types of regimes. Fast and shallow regimes must be detected |
15-11 |
| Regular |
Occurrence of 2 types of regimes. If fast and shallow regime is absent, scores must be lower. |
10-6 |
| Poor |
Predominance of only 1 type of regime. If the slow regimes predominate, scores must be lower |
5-0 |
| Channel sinuosity |
Higher channel sinuosity provides higher availability of habitats such as backwaters and the main flow channel. It increases the streams’ ability to retain flow fluctuations caused by heavy rains. Energy absorption by the bends protects the water body from excessive erosion and provides refuge for biota during peak flow events |
Optimal |
Occurrence of sharp and evident curves along the evaluated site |
20-16 |
| Good |
Channel sinuosity is not evident. Less sharped and more distant curves can be observed |
15-11 |
| Regular |
The site presents a few soft and distant curves |
10-6 |
| Poor |
The site is straight. In case of man-made plumbing (with cement or other material), the scores must be lower |
5-0 |
|
Parameter
|
Significance
|
Quality status
|
Interpretation
|
Scoring
|
| Water level amplitude |
Fluctuations in the water level affect the availability of substrates and shelter for the aquatic fauna and dictates sediment and nutrient transport through the stream. Constructions in cross and longitudinal sections of the streams alter the flow efficiency of the channel. Grounding, concreting and silting conditions cause loss of diversity and reduce the damping potential of flood events. Extended periods of drought reduce the amount of water available in the stream channel. High magnitude flow peaks carry organisms, nutrients and structures that promote environmental complexity. |
Optimal |
The water level is sufficient to include all available substrate underwater, suitable for colonization. |
20-16 |
| Good |
The water level fills more than 75% of the stream channel. Less than 25% of available substrate are exposed. |
15-11 |
| Regular |
Water level fills between 26% and 75% of the stream channel. Most of the available substrate are exposed. |
10-6 |
| Poor |
Very little water in the stream channel. Most of which is stagnant water in ponds. |
5-0 |
|
Parameter
|
Significance
|
Quality status
|
Interpretation
|
Scoring
|
| Channel integrity |
Channel integrity refers to changes in the structure of the stream channel, imposing restrictions on the survival of aquatic organisms and changing the hydrological dynamics of the streams. Dike formation, dredging, drainage, dams paving, and flow diversion are amongst some of the prejudicial alterations to aquatic ecosystem functioning. |
Optimal |
Absence or minimal occurrence of alterations such as pipelines, dredging, bridges, dikes, embankments, dams, concrete canalization of flow diversion. The stream follows a natural flow pattern. |
20-16 |
| Good |
Occurrence of older channel alterations such as bridges or dredging in up to 20% of the site, with no recent changes. |
15-11 |
| Regular |
Occurrence of dams, dikes, drainage or any of the aforementioned alterations that are recent, modifying from 21% to 50% of the natural course of the stream. |
10-6 |
| Poor |
Stream margins are covered with cement or supported by gabions. Alternatively, more than 51% of the stream channel is channeled, with flow disruption. |
5-0 |
|
Parameter
|
Significance
|
Quality status
|
Interpretation
|
Scoring
|
| Bank stability |
Stream banks comprise the area of soil immediately adjacent to the water body. Stable margins, with minimal occurrence of erosive processes favor the maintenance of the physical structure of the main channel and protect the biota. Unstable margins, in sandy soil regions, are prone to displacement of soil masses and high erosion, increasing siltation of streams. The evaluation must be performed on each margin separately and summed. |
Optimal |
Stream sections with minimal occurrence of erosive processes, with preserved and dense riparian vegetation supporting the soil. Up to 10% of the stream site presents small signs of erosion, as a natural process. |
9-10 |
| Good |
The site presents from 11% to 30% of the margins with sign of erosion, with soil exposure in sparse sections due to lack of preserved vegetation, colonization by grasses and herbaceous vegetation, roots exposed. Loss of soil masses that can be further colonized by terrestrial vegetation if the proper time is given. |
6-8 |
| Regular |
Erosive processes reach 31% to 65% of the site. Roots are exposed in the stream’s margins, with the domain of grasses, herbaceous or small arboreous vegetation. Minimal occurrence of arboreous vegetation and higher susceptibility to the effects of heavy rain. Clear and abundant sections with soil masses displacement, limiting vegetation succession. |
3-5 |
| Poor |
More than 66% of the banks are eroded, with clear signs of burial of structures and interruption of water flow due to silting. Absence or minimal occurrence of vegetation in the margins. Reach dominated grasses, herbaceous or small arboreous vegetation. |
2-0 |
|
Parameter
|
Significance
|
Quality status
|
Interpretation
|
Scoring
|
| Riparian bank protection |
Riparian vegetation contributes to the filtration of sediments and nutrient runoff. Riparian vegetation stabilizes the soil with its roots and protects the soil from the erosive action of rain and wind, through the formation of the organic layer of litter. The removal of the riparian vegetation to give place to agriculture, pasture and/or urban settlements exposes the terrestrial area to weathering and ecosystem function losses. The presence of lateral buffers (> 20 m) along the evaluation reach of 40 m are the most desirable condition for preservation. The evaluation must be performed on each margin separately and summed. |
Optimal |
More than 90% of the stream riparian area (site length of 40 m) is covered by natural vegetation, with arborous, shrubby, and herbaceous species, forming a multi-strata vegetation. No evidence of agriculture, pasture and/or urban land use in 20 meters lateral buffer. Plant species can grow naturally. |
9-10 |
| Good |
Riparian area covered by natural multi-strata vegetation from 70% to 89% of the stream site length (40 m). Minimal evidence of agriculture, pasture and/or urban land use in 20 meters lateral buffer. No representative discontinuities in riparian vegetation. |
6-8 |
| Regular |
Riparian area covered by few arboreous vegetation from 50% to 69% of the stream site length (40 m). Evident occurrence of occupation for agricultural, pasture and/or urban activities where natural vegetation is absent. Whenever urban land use occurs, scores are lower. |
3-5 |
| Poor |
Less than 50% of stream riparian area covered by any kind of natural vegetation. Large discontinuities or absence of arboreous vegetation. Dominated by herbaceous vegetation and grasses. 20-meter lateral buffer occupied by agriculture, pasture and/or urban land use. If urban use predominate, scores must be lowest. |
2-0 |
|
Parameter
|
Significance
|
Quality status
|
Interpretation
|
Scoring
|
| Vegetation conservation on the riparian zone |
Preserved riparian vegetation is represented by the occurrence of plants with different sizes, shapes and colors. Which include trees, shrubs, herbaceous, epiphytes. Most preserved areas are inhabited by native species. The increase in the presence of exotic species is indicative of deterioration. The evaluation must be performed on each margin separately and summed. |
Optimal |
Riparian vegetation is composed of native species in a good state of conservation. There are distinct vegetation strata, with diversity of sizes, shapes, and colors. |
9-10 |
| Good |
The riparian vegetation is composed not only by native species, but also exotic species, although in a good conservation status. There are distinct vegetation strata, with diversity of sizes, shapes and colors. Minimal evidence of anthropogenic impacts. |
6-8 |
| Regular |
Higher occurrence of exotic tree and shrub species, within a more homogenized landscape. Predominance of medium sized trees, within clearing spots. Evident anthropogenic impacts, with predominance of grasses and small trees |
3-5 |
| Poor |
Riparian vegetation is absent or with minimal coverage along the stream site. Few occurrences of medium sized trees. If the riparian area is completely replaced by impermeable surfaces such as in urban landscapes, the scores must be lowest. |
2-0 |
Protocolo de Avaliação Rápida para riachos que drenam por formações areníticas: uma ferramenta de avaliação versátil e efetiva
Thumbnail
Thumbnail
Thumbnail
Thumbnail
