So what is the first step in planning a micro hydropower system? Go swimming! We certainly got our feet wet at Tah Po Pu, a Karen village in Tha Song Yan Province in northern Thailand. Upon our arrival, we were greeted with friendly handshakes and 'Tableu' from the adults, warm smiles from the children who, bursting with curiosity, followed us up the steep slope along the water fall to the weir site. The site we chose is about 36 meters above the powerhouse site and features large rocks and other ratures that may help us construct a sturdy cement weir. We brought along our trusty water-resistant notebook, a 100-meter measuring tape, a shorter measuring tape, a stopwatch, and our inquiring minds. We were going to find out the volumetric flow of the river, the penstock pipe length, and the transmission wire length.
To measure the flow, we chose two places in the river well away from the water fall. For each one, we measured the length across and the depth of the river at regular intervals so that we could calculate the cross-sectional area. This part required shallow wading at one of the locations, but a brave act of sacrifice at the other location. Our fellow BGET volunteer Christina waded in past her waist, getting almost completely wet putting the measuring stick into the fast-flowing water! I had just gotten over Dangue and that is my excuse for simply standing by in awe. After finding the area, we measured a length down the stream to float an object so we could find how long it would take this section of water to move a certain distance. Leaves worked okay, but they often sunk pathetically, even to our desperate chants of "Go! Go! Go!" Empty water bottles seemed to work best. In the end, we multiplied the float length by the area and divided by the float time to find the volume of water flowing per unit time in liters per minute.
On our way back, we were followed by some Karen children, chasing the ones in front of us, we merrily made our way back to the village, measuring the distance along the way to estimate the pipe length from weir to powerhouse. We were finished for the day, as far as the site survey went. Tired from the cold, rushing water, we lay and sat in one of the houses while our friend Sunti made us a delicious pork and vegetable dish. We sat in a circle on the floor and ate hungrily, pouring the hot food onto mounds of white rice. Later that night, there was a village meeting at the house of one of the village leaders. The BGET volunteers sat silently while about forty or so men spoke in Karen to one another, gathering the gist of it from body language and tone of voice. As is the way of most Karen, there was alot of laughter. If only I knew what they were saying!
After a night of sound sleep, we awoke, ate, and proceeded to measure the transmission line length. Along with the height of the water fall, which was measured earlier, we now had all the measurements needed to size the system. We thanked those who had let us stay and eat with them and said farewell to the children, but it was not a sad goodbye. We'll be back at the end of November for the installation!
