Consulting a licensed dam engineer would be preferable, due to liability, etc. Wet clay would be difficult to apply and properly compact. Water release from upstream pond would be best diverted and piped or pumped around construction site. Bentonite clay is a hazardous type material that is sometimes injected to help plug leaks. It is best to follow engineering standards for type of clay, moisture of clay/clay mix, compaction frequency of lift layers, dimensions of clay core relative to dam size, etc. The potential of dam design and failure increases when engineering review is not included, increasing liability if considered negligent if civil actions occur. There are various internet papers on small dam design, construction and management. Providing a bypass channel to prevent overflow and mechanism to help lower or drain dam is desirable to help manage dam and prevent overflow during extreme flood periods. When the moisture level in the clay meets or exceeds its liquid limit, it becomes plastic and prone to failure. There are various engineering and soil material tests that test compatibility at various moisture levels and liquid limit.

I explained in my article. It’s in my researchgate profile. The subject is The 3D analysis and estimation of transient seepage in earth dams through PLAXIS 3D software: neural network.

https://ui.adsabs.harvard.edu/link_gateway/2019EES....78..571B/doi:10.1007/s12665-019-8405-y

The question is explained in my reresearchgate. The subject is 2D and 3D Modeling of Transient Seepage from Earth Dams Thorough Finite Element Model (Case Study: Kordaliya Dam). I have 4 articles in my researchgate about this topic.