The map shows that the so-called moat was really an irrigation canal or ditch that serviced the fields in the surround area. It filled the role of a moat. You can see that the canal has been since filled in by looking at the last image, which is from a Google Maps satellite image.
Notice also the odd shape drawn behind (to the east) of the building. This appears as a cluster of dense woods and shrubs on the satellite photo. The three photos that follow are photos of that wooded area taken from three angles, all on the south side. The first was taken close to the southeast corner of the house. You can see that the cluster of greenery is actually mounded up and was used at one point as a kind of root cellar.
The following two photos help verify the angle of the first. The third shows the round brick tower. This is also visible on the aerial photo as is the stone structure in the background to the right. The fourth photo was taken from the east end of the mound looking back toward the chateau. In the distance you can see the chimneys of Mullenark. Those same chimneys are visible also in the fifth photo.
Using the distance measurement tool on Google Maps, I measured the distance from the chateau court to the middle of the mound at about 50 yards. If you take a moment to look at the area on Google maps you can make out the roof of the brick tower in the southeast corner of the clump of trees.
Read this quote from Lee's memoir: "As we continued around to the rear of the castle my first face-to-face confrontation with the enemy occurred. I stepped around a large clump of shrubbery and there was a German private, rifle in hand but with no heart for the fight. He became our first P.O.W. of the day. Situated on a direct line between the castle and the Roer River was a large storage cellar. Here we decided to stop, regroup and await the out come of the company's thrust against the castle itself. We were not aware of the desperate plight of our comrades. They had come under severe mortar and small arms fire and were pinned down on the banks of the moat. Our position was relatively strong and reasonably safe. The cellar was constructed of brick in the walls, a stone floor and a thick dirt covered roof. By now it was full day light and the German garrison in the castle sent a lone soldier from the rear of the castle toward the river and the main German lines. As he approached our position we invited him in and he wisely accepted. This same scenario was repeated over and over during the morning hours until we had collected twelve prisoners and had placed them along the wall on one side of the cellar. Finally the enemy came to realized what was happening and opened mortar fire on our position. They would drop a round at the doorway and the shrapnel would fly through the opening. We were protected by the heavy brick front walls which provided an area of safety on each side of the cellar. The day wore on and late in the afternoon we decided to leave the cellar and make our way around the back of the castle and into the small village on the opposite side."
It seems probable that the mound pictured in these photos is the cellar Lee mentioned: large, with heavy front walls, a thick dirt roof, on a direct line between the castle and river, and in proximity to clumps of shrubbery. Frank Perozzi added that is was a ground level storage cellar and had straw on the floors. It is also the right distance from the castle. The mortar squad was located in the courtyard of the castle.
Lee earned his star when he made the circuit around the castle the next night and helped evacuate his fellow infantrymen who were pinned down on the banks of the canal. Frank Perozzi said he always felt Lee should have received a Silver Star for leading his squad in the capture of the twelve prisoners.
