Factors affecting capillary rise

Capillary rise $h_c = \dfrac{4T\cos\alpha}{\gamma_w d}$ depends on:

1. Grain/pore size: smaller effective diameter $D_{10}$ and void size gives greater rise ($h_c \propto 1/d$; $h_c \approx C/(eD_{10})$).
2. Void ratio: smaller $e$ gives higher rise.
3. Surface tension of water (and temperature, impurities).
4. Contact angle between water and particle surface.
5. Soil type and packing, clean surfaces and degree of saturation of the soil.