The ground raycast at (8,-7) hits the ground at -1.18 — but the water is at 0.25! The water should be hit FIRST from above. Unless the water disc object isn't being considered in the raycast (ray_cast only checks the ground mesh). But in the render, the water was only visible when the ground was hidden — meaning in the render, the GROUND is drawn over the water.

This is very strange. The ground at the pond center is at -1.18 (below water 0.25), yet in the render the ground appears instead of water.

OH WAIT. I bet the issue is the water disc is INSIDE the ground mesh — the ground mesh is one solid grid, and the water disc is a separate flat disc. In Cycles, when the water disc is at z=0.25 and the ground at z=-1.18 below it, the water should be hit first. Unless the ground mesh has a face that overlaps the water at a HIGHER z...

Actually, let me reconsider: maybe the render from directly above was actually showing the water but the water material was restored to transmission=1, making it show the ground below through transmission! When I hid the ground, the water showed (teal). When the ground is present, the water is TRANSPARENT (transmission 1.0, no absorption) and shows the ground below! The center pixel 0.12,0.12,0.08 from above is the ground at -1.18 seen through transparent water.

That's it — the water is fully transparent (transmission weight 1.0 with no color absorption), so it looks like the ground. The water material needs to be less transparent — add some absorption or lower transmission, or make it mostly reflective with a tint.

For a pond, a good approach: transmission weight ~0.8 with absorption color (deep teal), plus roughness. Or use a mix of glossy reflection and transmission. In Cycles, glass-like water with transmission 1.0 shows everything behind. For a nice pond look: base color teal, transmission weight 1.0, but add an Absorption node (Volume) or reduce transmission and add glossy.

Simplest fix: keep transmission but add a colored absorption volume (ShaderNodeVolumeAbsorption with a deep green-teal color, density ~0.5-1), so the water has visible depth and color. Or use transmission weight 0.7 + a slight glossy component.

Actually in Cycles, for thin water surfaces (a flat disc), there's no volume — absorption won't work without thickness. The water disc is infinitely thin, so transmission shows the bottom. Options:
1. Make the water a semi-transparent glossy: transmission 0.35, roughness 0.05 — gives a reflective sheen with some see-through.
2. Add a second water layer (a solid "water body" mesh filling the depression) with absorption.
3. Use the transmission with a mix: 60% glossy (reflection) + 40% transmission.

The best look for a pond seen from a distance: mostly reflective with subtle transparency. Let me use Mix Shader: 0.65 glossy (with teal tint, roughness 0.06) + 0.35 transmission (teal). And keep the noise bump. That will show sky reflections (warm sky → warm reflections) and some bottom.

Also — the terrain around the pond rim is above water level (0.35-0.55), so the visible water is only where terrain < 0.25. From the camera's angle, the pond should be clearly visible.

Let me fix the water material.

import bpy

mat = bpy.data.materials.get('WaterMat')
nt = mat.node_tree
# clear all nodes except output
for n in list(nt.nodes):
    if n.type != 'OUTPUT_MATERIAL':
        nt.nodes.remove(n)

out = nt.nodes.get('Material Output')

# Principled: reflective teal with partial transmission
bsdf = nt.nodes.new('ShaderNodeBsdfPrincipled')
bsdf.inputs['Base Color'].default_value = (0.06, 0.16, 0.14, 1.0)
bsdf.inputs['Roughness'].default_value = 0.05
bsdf.inputs['Transmission Weight'].default_value = 0.45
bsdf.inputs['IOR'].default_value = 1.33
bsdf.inputs['Specular IOR Level'].default_value = 0.9

# glossy for strong reflections
glossy = nt.nodes.new('ShaderNodeBsdfGlossy')
glossy.inputs['Color'].default_value = (0.55, 0.75, 0.72, 1.0)
glossy.inputs['Roughness'].default_value = 0.06

mix = nt.nodes.new('ShaderNodeMixShader')
mix.inputs['Fac'].default_value = 0.55   # 55% glossy reflection
nt.links.new(glossy.outputs['BSDF'], mix.inputs[1])
nt.links.new(bsdf.outputs['BSDF'], mix.inputs[2])
nt.links.new(mix.outputs['Shader'], out.inputs['Surface'])

# noise bump
noise = nt.nodes.new('ShaderNodeTexNoise')
noise.inputs['Scale'].default_value = 1.2
noise.inputs['Detail'].default_value = 5.0
bump = nt.nodes.new('ShaderNodeBump')
bump.inputs['Strength'].default_value = 0.25
bump.inputs['Distance'].default_value = 0.05
nt.links.new(noise.outputs['Fac'], bump.inputs['Height'])
nt.links.new(bump.outputs['Normal'], bsdf.inputs['Normal'])
nt.links.new(bump.outputs['Normal'], glossy.inputs['Normal'])

print('water material rebuilt')