Research on this issue may be available in Chinese language.

I found the following study in English:

Macroinvertebrate distribution and aquatic ecology in the Ruoergai (Zoige) Wetland, the Yellow River source region, Frontiers of Earth Science, 2017, 11(3): 554-564. doi: 10.1007/s11707-016-0616-x

It includes Tab. 2 Taxa list of macroinvertebrates in the Ruoergai Wetland.

The study area includes parts of Sichuan province.

"Figure 1 shows the locations of the study area and the sampling sites. The Ruoergai Wetland is located at the northeastern edge of the Qinghai-Tibet Plateau. The total area of the wetland is about 16,000 km2 (Li et al., 2014). The landform is hilly, with altitudes of 3400‒3900 m. The annual mean temperature is approximately 1°C, and the annual mean precipitation is approximately 650 mm. It includes Ruoergai, Hongyuan, and Aba Counties in Sichuan Province and Maqu and Luqu Counties in Gansu Province. The Hei River and the Bai River are the two main rivers flowing through the Ruoergai Basin."

Abstract:

The Ruoergai (Zoige) Wetland, the largest plateau peatland in the world, is located in the Yellow River source region. The discharge of the Yellow River increases greatly after flowing through the Ruoergai Wetland. The aquatic ecosystem of the Ruoergai Wetland is crucial to the whole Yellow River basin. The Ruoergai wetland has three main kinds of water bodies: rivers, oxbow lakes, and marsh wetlands. In this study, macroinvertebrates were used as indicators to assess the aquatic ecological status because their assemblage structures indicate long-term changes in environments with high sensitivity. Field investigations were conducted in July, 2012 and in July, 2013. A total of 72 taxa of macroinvertebrates belonging to 35 families and 67 genera were sampled and identified. Insecta was the dominant group in the Ruoergai Basin. The alpha diversity of macroinvertebrates at any single sampling site was low, while the alpha diversity on a basin-wide scale was much higher. Macroinvertebrate assemblages in rivers, oxbow lakes, and marsh wetlands differ markedly. Hydrological connectivity was a primary factor causing the variance of the bio-community. The river channels had the highest alpha diversity of macroinvertebrates, followed by marsh wetlands and oxbow lakes. The density and biomass of Gastropoda, collector filterers, and scrapers increased from rivers to oxbow lakes and then to marsh wetlands. The river ecology was particular in the Ruoergai Wetland with the high beta diversity of macroinvertebrates, the low alpha diversity of macroinvertebrates, and the low taxa richness, density, and biomass of EPT (Ephemeroptera, Plecoptera, Trichoptera). To maintain high alpha diversity of macroinvertebrates in the Ruoergai Wetland, moderate connectivity of oxbow lakes and marsh wetlands with rivers and measures to control headwater erosion are both crucial.

Rudolf Pfister

Many thanks for this very useful answer ! It looks like a really good reference to have an idea of the different macroinvertebrate families in the area, and this is quite close to some of the sites I will study.

I've been looking for papers in Chinese (and I'm still looking for some), but these papers seem to be rarely referenced by scientific web search engines. And when they are, I rarely successfully access them.

Also found this paper, where they are pre-occupied with creating multimetric indices, and lots of references (but not related to Sichuan):

HUANG Qi et al (2015)

Development and application of benthic macroinvertebrate-based multimetric indices for the assessment of streams and rivers in the Taihu Basin, China

Ecological Indicators

Volume 48, January 2015, Pages 649-659

Article Development and application of benthic macroinvertebrate-bas...

Highlights

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Multimetric indices (MMIs) based on benthic macroinvertebrates were developed and applied in the Taihu Basin.

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We developed two MMIs for two specific aquatic ecoregions in the Basin.

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The MMIs were robust and sensitive to anthropogenic ecological impairment.

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The general ecological status of the Taihu Basin was lower than “good” status.

Abstract

The development of biological indicators for assessing ecological conditions in streams and rivers is urgently needed in China, particularly in heavily impacted regions. The aim of this study was to develop and apply benthic macroinvertebrate-based multimetric indices (MMIs) for the assessment of streams and rivers in the western hill and eastern plain aquatic ecoregions of the Taihu Basin. MMIs were based on samples collected from October 16 to November 8 2012 at 120 sites in streams and rivers. Least disturbed sites defined the reference conditions. Chemical water quality, physical habitat, and land use were used as criteria to identify reference sites in the basin. Metrics related to benthic macroinvertebrate richness, composition, diversity and evenness, pollution tolerance, and functional feeding groups were screened by range, sensitivity, responsiveness, and redundancy tests. Total number of taxa; percentage of Ephemeroptera, Trichoptera and Odonata (% ETO); Berger–Parker’s index (BP); Biotic index (BI); and percentage of filterers–collectors (% FC) were used to construct the MMI for the western hill aquatic ecoregion (MMIW). Total number of taxa, percentage of Crustacea and Odonata (% CO), BP, BI, and % FC were used to construct the MMI for the eastern plain aquatic ecoregion (MMIE). The MMI scores were obtained by combining the rating categories (excellent, good, fair, poor, and very poor). The MMIs were tested using a separate subset of the data, and the results indicated that the newly developed MMIs were robust in terms of percentage of sites correctly classified, coefficient of variation, box-separation ratios, and separation powers. The ecological status was then evaluated based on the MMI scores. The results indicated that the general ecological status of streams and rivers in the Taihu Basin was rated lower than “good”, the western hill aquatic ecoregion was rated “fair” and the eastern plain aquatic ecoregion was rated “poor”. Moreover, the MMIs showed a significant negative response to an increasing gradient of disturbance. Therefore, these preliminary MMIs can be used as assessment tools in ecological biomonitoring and management of the Taihu Basin.

As for scientific papers in Chinese, you need access to the CNKI database, which covers most of the production. It's not clear, where you can access it in France; but the best descriptions etc. you find on CrossAsia https://crossasia.org/en/resources/databases/ > CNKI is China academic journals : 中国期刊全文数据库. (It needs personal insitutional access, if you have some cooperating institution in Germany).

For specialised literature on biology, see China Scientific Book Services: http://www.hceis.com

Thanks again for these new answers.

The paper you shared is very helpful, even if it's not from Sichuan. In the references, I found this :

Morse, J.C., Yang, L., Tian, L., 1994. Aquatic Insects of China Useful for Monitoring Water Quality. Hohai University Press, Nanjing.

I will try to find this book, it seems very useful. Otherwise, I guess Fauna Sinica Invertebrata will provide all the information I need, but there are too many volumes and too much information. I don't even know if these books contain keys to families.

I'm starting to feel like I'm going to far, and that for identification to the family level keys from North America or Europe could be fine. Especially if I already have an idea of which families are present in China.

I've been trying to access CNKI database without success for now, but thanks for these links anyway.

Difficult to know for me, what is far and what is too far :)

The book you need is on sale here, and in English: https://www.chinascientificbooks.com/aquatic-insects-of-china-useful-for-monitoring-water-quality-p-1286/