Friday, February 7, 2014


After several months of planning, several weeks of construction, several long days of set-up, and lots of hard work and ingenuity by all involved, we finally got the streams running smoothly! It was so exciting to finally see the whole array spinning along, 12 little streams ready to grow biofilms under different treatments and hopefully tell us something about how inputs from large wildlife influence the way the whole river functions.

After getting the experiment started and running smoothly, we finally made it down to our main camp in the Mara, where we celebrated our success with a sundowner!

Celebratory sundowner!

Thursday, February 6, 2014


Again, I can only blame irrational optimism for not thinking we might have some trouble with leaks from streams made out of PVC canvas. Chris and I had done a test on one of the streams, by filling it with water and leaving it outside for a couple of days. When it still held water, we were excited and moved on. But filling 12 streams sitting on bare ground with a precise amount of water was whole different level of testing. 

Just as we were wrapping up our set-up and getting ready to officially start the experiment, we noticed water slowly leaching out of about half of the streams and onto the bare ground around them. We had rulers in each stream, so we could see how much the level was falling in each one. There was some banging of heads against the wall (mine), and some reassuring this was an easy fix (Chris), and some general debate about the importance of this factor (all) before deciding we needed to try to patch all the leaks... in our streams already filled with gravel and water. 

David and Emma watching a stream leak
First we had to pump enough water out of each leaking stream to be able to dry the leaking area, and keep track of that volume of water so we could replace it once the leak was fixed.

David pumping water out of a stream to patch the leak
 Then we patched the inside of the streams with liquid electrical tape and the outside with waterproof silicon and waited for it to dry.

Emma waiting for the silicon patches to dry
 Then we re-filled all the streams and waited to see if the leaks had stopped...


Wednesday, February 5, 2014

Building the streams

Setting up our experimental stream array turned out to be no small feat! In some bizarre moment of optimism, I had scheduled one day to get the streams up and running. Impressively, it only took two and half days, which I still consider a win. There were a number of steps along the way, and I don't think we could have done it without everyone's contributions and help. 

There were a number of opportunities for innovation and ingenuity, like when we realized we had the wrong couplers for our shafts, and David and Emma improvised a solution out of electrical tape and tubing. Or when we realized that all of the electronics we had ordered to control the motors to turn the paddlewheels came without any wiring, and Chris ordered wiring from Nairobi and spent the day figuring out how to wire US devices to an unreliable Kenyan power supply.

Chris wiring our motors
There was also lots of just hard work, like having to measure out the exact number of liters of water to add to every stream and the hand carry it with buckets.

Emma measuring out water
Chris and Emma filling buckets
David filling streams
Or realizing the ground had to be perfectly level to have a 6 m long shaft turn 6 paddlewheels at equal depths, and having to adjust the ground under each stream by hand, despite the risk of cuts from the sharp flashing edges.
WRUA members helping with the setup
But by the end of two days, we had all the streams set up and filled with water, the motors running, and the paddlewheels circulating the water around the streams. But just when we were ready to declare victory, an unexpected problem arose...

Tuesday, February 4, 2014

Emma in the Mara!

After David had been in the Mara for one week, one of my other professors, Dr. Emma Rosi-Marshall, flew in for a two week visit as well. Emma is a scientist at the Cary Institute of Ecosystem Studies, and her research focuses on large river ecology and the influences of human inputs on river ecosystems. Emma's knowledge and experience working on rivers has been invaluable in helping us learn how to study the Mara, and her research on human inputs is critical to helping us sort out the effects of hippos versus people on the river.

Emma also has an experimental stream array she designed at the Cary Institute, and we based our experimental streams in the Mara on her designs, so it was great to have her here to help out with the start of the experiment.

Michael, Amanda, Emma, and David picking up the stream parts
Emma's first stop in Kenya was at a welding shop in Narok, where a very skilled welder named Michael Otieno had crafted paddlewheels, shafts, motor mounts and ball bearing stands to impressive precision out of simple materials based on some sketches in my notebook. Not the most glamorous way to be welcomed to the Mara, but as an avid river ecologist, Emma was excited to see the Kenyan version of her streams coming to life. By the end of the her first day in Kenya, all the pieces were in place to start actually building our streams.

Monday, February 3, 2014

David in the Mara!

The last few weeks have been some of the busiest, but most fun and successful, of our entire field season. My advisor, Dr. David Post, came in from Yale in mid-January to spend two weeks in the field with us. David visited us in the Mara in 2011, and his insights on the system were invaluable in helping shape our research questions, so we were really excited to have back in the Mara to see what we had accomplished since then. 

David was excited to see some more of the Mara than he had seen during his last visit, and I think we delivered. Within his first week in Kenya, we had driven 1,600 km (mostly on dusty, bumpy dirt roads) and he had only spent two nights in the same place once.

David Post and Amanda at the Rift Valley overlook
Our primary goal during David's first week in Kenya was getting the experimental streams up and running. After determining that running the streams off of solar power would be cost-prohibitive, we decided to run the experiment at the Water Resource User's Association (WRUA) in Mulot. This location has several advantages. It has a main source of power, a water pump and tank system already in place, good security, and a location for Geemi to camp while he helps out with this experiment. Most importantly, it allows us to work with the WRUA and inform them more about our research in the Mara. The WRUA has been an active and important force for improved water and land management in the Mara for a number of years now, and they just recently won the Thiess International Riverprize!

David talking with some of the WRUA members about the streams
By the end of David's first week, we had laid the groundwork for not one, but two exciting experiments to undertake in the Mara! More details to come...