For any river that we see in our natural environment to flow healthily, it needs to be protected with forests, where it starts. Similarly for us to feel the full effects of the river, the flow of the Spirit, we need to surrender all, we need to listen to the Spirit, we need to keep spiritual songs in our heart, we cannot regard iniquity in our hearts. This protects the river's flow in our hearts. When the area where a river starts is deforested, the river ceases to flow. Likewise we can cause the Holy Spirit to cease to work with us.
Garbage can pollute the river as it flows.
So we can pollute the flow of the Holy Spirit by feeding the flesh more than the Spirit. As the river flows, it provides liquids and a habitat for birds and other animals. It also serves the land. So likewise as the Spirit flows through us, He moves us to serve others at all times. Unselfish giving as displayed by our Saviour Jesus.