Materials in the water system
The environment affects water surfaces in ways beyond winds and currents. A river thick with mud or crushed stone is less smooth and transparent than a freshly cleaned swimming pool. Suspended particulates or air bubbles, and depth all have a significant impact on water's appearance.
Appearance properties for HDRP's water implementation make it possible for you to adjust the water Material in a physically plausible way.
Smoothness
At a distance, it is harder to perceive the details of a water surface. Adjust the Close and Distant properties to determine how close to the camera HDRP should start to reduce smoothness in order to simulate the way distant reflection behaves in the real world, where specular reflection appears larger at a distance.
Refraction
If you increase Absorption Distance the camera can see further into the water. A higher Absorption Distance makes caustics and the refraction effect controlled by Maximum Distance more visible.
The Maximum Distance property determines the point in meters from the camera at which HDRP no longer renders the refraction effect. A higher value increases distortion.
Scattering
As you increase the values of the first three properties in this section of the Appearance properties, the water surface becomes both brighter (as captured light diffuses through the water) and more opaque (because it begins to absorb more light and let less through).
Direct Light Body Term and Direct Light Tip Term (the second of these is only for Ocean, Sea, or Lake water surface types) increase the intensity of light visible through waves, as at the wave tips in the screenshot below. Direct Light Tip Term is most visible at grazing angles.
Custom Materials
To create a custom water Material, copy the default water Material and adjust that copy. The water ShaderGraph documentation provides more information about which properties you can adjust.