Experimental study of water quantity exchange between fissures and sinkholes under different recharge modes in the fissure-conduit media

To explore the movement of groundwater between fissures and sinkholes under different recharge modes through a fissure-conduit medium model, the HD camera and colored tracer are adopted to observe the movement of groundwater in a karst groundwater system. In this paper, we design three kinds of recharge mode: recharge only through fissures, recharge through both the sinkholes and fissures and separated recharge through fissures and sinkholes at the same time. The results indicate that the influence of the sinkhole on the diffusion of the fissure water decreases with the increasing distance between the fissure and the sinkhole. Compared with the recharge mode only through fissures, sinkholes have more influence on the diffusion of the fissure water when recharge through both sinkholes and fissures exists. When separated recharge through sinkholes and fissures with equal water quantity exists simultaneously, only the groundwater in fissures flows into sinkholes.