Journal Entries



——Hydroponics 2020/2021——

14 December 2020- Update
Research Paper:

16 September 2020- Methods Paper
This year, since we are continuing remote learning, I will be focusing on writing. It is my last year in WISRD, so I believe it is very important to leave a legacy behind. Therefore, the Hydroponics Group will be writing a Methods Paper with the help of Proffessor Moreno. This paper will outline our experience and the complete construction and reasoning behind our lab.

31 August 2020- Summer Experiment Overview
As school moved to remote learning in early March, Sadie took the lab home and is conducting an experiment in her garage. The lab structure and concept has remained practically the same. She added a new lightfixture and plastic covers to the reservoir.



——Hydroponics 2019/2020——

5 Feburary 2020- Week 3 Observations

2 October 2019- Germination Observations

2 October 2019- Germination Station

2 October 2019- Germination Plan

18 October 2019- Little Gem Lettuce
Earlier this week, the team decided to move forward with growing Little Gem Lettuce. We decided that it was a hardy lettuce suitable to our environment. It grows pretty quickly so we would be able to run multiple iterations quickly.

7 October 2019- Plant Contenders

We have started to think about what plants we want to grow. Right now we are looking at different types of lettuce, spinach, and beans. We are leaning towards leafy greens because physical observations will be fairly easy to make. Additionally, the San Joaquin Valley produces the majority of lettuce and spinach. I have found multiple references from different university that we could use to help guide us. A few helpful websites will be linked below.

University of Florida –
Have multiple publications on:
Crops grown
Greenhouse design + production
Shade house + high tunnel design and production

UC Davis –
Vegetable Research and Information Center
Have information on:
San Joaquin Valley agriculture
Vegetable information

2 October 2019- Change of Plants

The Hydroponics team has decided to change the species of spinach we are growing in our lab. We have switched from Mustard Spinach to Malabar, or Basella Alba, Spinach. We made this decision with the intention of replicating a more realistic situation; Malabar Spinach is more commonly grown in the San Joaquin Valley than Mustard Spinach is. Along with this, we are figuring out how to create nutrient solutions for our lab. I am planning on meeting with Tim, Alicia, and Loli for guidance on how to approach this.

——Hydroponics 2018/2019——

1 May 2019 - Salinity Calibration + Values

We are currently in the process of calibrating our salinity sensor. We have been testing 1-mole solutions and have come up with very high percent errors. We are planning on making and testing a 35 ppt solution as an alternative to see if there is something faulty with the wiring or if there’s error in our procedure. 

We found a very useful research paper, Water Stress and a Changing San Joaquin Valley, and have set our salinity values for our lab around it. We have decided to test 0.6 M (35 ppt), 0.025 M (1.5 ppt), and 0M (0 ppt). The ocean water has a salinity level of 0.6 M (35 ppt), so we know that its an environment in which our plants will not survive. The value 0.025 M is derived from what the research paper deems dangerous salinity levels in the valley. We will adjust out median salinity value to see the limit of salt our plants can withstand. Lastly, we will, of course, have a standard to which we can compare the growth of our plants. 

*Water Stress and a Changing San Joaquin Valley can be found in the team drive or in server assets/life science/hydroponics/bibliography

25 April 2019 - New Lab Test Run

Today, Nicholas and I test ran the lab for the entire class period, below are some notes.

Test Run: 4/25/19

  • run time: class period – 75 minutes
  • weird gurgling noise
    • could be a sign of not enough water in the system
  • water level fluctuates
    • during gurgling sound, it falls
    • doesn’t overflow/hasn’t overflown yet
    • will this affect our data/the circulation of nutrients and salt?
  • is water flow to strong
    • will plants be able to get nutrients?

13 March 2019 - Frame of New Lab

Sadie has constructed the first part of the frame of our new lab (Figure 1). The plan is to have a system with two valves, controlling the water flow into the reservoir as well as the grow tubes. However, the plan is to have the water move upwards into the grow tubes; the grow tubes are resting on top of the system. I am concerned about the functionality of this system design. Even though we have a valve controlling the flow into the reservoir, I fear not being able to get the water upwards and keeping a consistent water level. I plan on testing the system to ensure it properly works.

Jack and I started a print* on a cap connecting the PVC to the poly. We will test it out tomorrow and print out more copies if it fits.

*filename on server: Newwer PVC Nozzle

27 February 2019 - Finalized Design

The hydroponics team has chosen a design to move forward with (pictured below.) This design has many advantages:

  1. the PVC pipes on top of each other allow for more support in the lab
  2. this design effectively uses the space and some materials we already created/have
  3. a blend of all our designs


  • → denotes possible support beam
  • Shaded areas are water reservoirs
    • Circles on the water reservoir are clamps

6 February 2019 - Multiple Designs

We have two redesigns for our lab. One is shown in the previous journal entry, the other shown below:

We have yet to decide which design to move forward with. Our second lab design uses our space more efficiently and designed to permanently run our lab. However, it would be more time consuming to build. Jack is currently working on the design.

In the meanwhile, Sadie and I will be focusing on running a preliminary lab. We will start growing our control and navigating the transplant and growth of the plant. This will enable us to have some experience when we officially start running our experimental lab. Our set up will be very basic and we will only be utilizing one grow tube. We have yet to pick a valve design to move forward, we will be experimenting on Monday once the caps have finished printing.

31 January 2019 - New Lab Design Progress

We have been working on many things

  1. We are completely redesigning our lab due to our siphoning problem
    1. After some time, the air inside our valve system runs out, sealing the pathway to the grow tubes. This forces all the water into the reservoir. To combat this, we are redesigning our lab this time with a second level.

                 our new hydroponics lab draft

  1. we are germinating our spinach and will move them into our lab once our lab is built
  2. nicholas is working on our hydroponics website which will enable us to control and monitor our lab
    1. camera, pH, light, pump, salinity, temperature, humidity, as well as a graph of variables over time
    2. the placeholder website is

17 December - Valve System Notes

Test Run 12/17

    • Worked really well (this might be it yay!!)
    • Adjust cap to adjust the water level
    • Can we run it for a day to make sure it works properly
      • Valve runs to grow tubes
      • Shortest PVC runs to reservoir
      • Long PVC connected to pump
    • How can we integrate into our lab w/o it taking up too much space

    • We are going to need 3 

  • Connect functional PVC to structural PVC
    • Minimize space
    • Clear PVC for water transport system, monitor water

13 December - Valve System Notes

Test Run 12/13

    • Cut 3 pieces of poly (total)
    • We couldn’t get water to flow to the grow tubes unless the reservoir tube was closed
    • Possibly change valve to reservoir side
    • Prioritized shortest pipe
    • Put pump on shortest pipe?
    • Will consult Joe and Bob



      • Not enough pe to go up
    • Integrate to skeleton
  • Smaller pipe on reservoir end? ( ½ in)
    • New caps

5 December - PVC Glue Testing + PVC Connector Nozzle Caps

During our meeting on Tuesday, Joe advised us to use Christy’s PVC Pipe Cement to securely glue our caps. Sadie (refer to her journal for more info) and Jack tested the durability of the glue. They concluded that the glue was strong enough to hold our caps and pipes together. However, when we looked at their experiment, we found that the 3D rectangle was coming apart. We think this might be because we are binding different plastics together. However, this could also be due to the method of application. To be sure of our theory, we conducted our own experiment. We glued on another rectangle as well as a ring (a prototype of our PVC nozzle cap). After conducting our experiment, we concluded that although the glue is strong, it doesn’t do anything more than bind pieces together; only acts as a glue. We were barely successful at melting the 3D printed rectangle in a small section. There are more, less toxic, alternatives to binding our pieces together.

We’ve made a few adjustments to our PVC connector caps: the nozzle is thinner and longer (to accommodate to the hose clamps and polycarbonate piping). The part is currently printing and we will test them later.

PVC connector nozzle caps file path: assets – 3D Print – 3D Prints – Hydroponics – NX Nozzle Cap PVC
the file is also saved on the Ultimaker2 Extended+

28 November - Basil Observations 2

The basil plants that the team uprooted died. We are thinking about germinating our basil plants ourselves. We’ve been brainstorming about how to continue our lab and fix all the problems we’ve encountered. I’ve created a brainstorming document to keep track of all this.

12 November 2018 - Basil Observations

To keep track of our progress, I’ve created a live basil observations document. This will be updated every WISRD class, 3 times a week.

29 October 2018 - Postponed Lab Run Date

Due to a couple of incidents, the date we’d originally planned to formally start running the lab has been postponed. Refer to the Hydroponics Homepage for the detailed plan.

  1. We found an error in our caps
    1. When we originally designed the caps, the nozzle was in the center of the cap, so the weight was easily distributed. However, when we changed the design of our cap, the distribution of weight was thrown off. This resulted in a weak spot below the nozzle and thus explains why 3 of our caps broke. Nicholas has fixed this and made this spot thicker. We will reprint all 4 caps.
  2. Instead of hanging our tubes, we will simply zip tie them to our frame
    1. this is just a simpler method of supporting our tubes

Without the caps, we can’t move forward with our lab. Now, our lab run date is looking around mid-November.

15 October 2018 - Update

After talking with Joe, we have come to 3 conclusions to make the startup of our lab quicker.

  1. No more stabilizers
    1. Instead of having stabilizers, it is easier to just suspend our tubes with rope. This method will eliminate the hassle of the stabilizers. Figure 1:  sketch of our plan.                                                                  Figure 2: how it would look implemented in our lab
  2. Cap Design
    1. We will only be using one cap design for our lab [Figure 3]. This way, we will be able to avoid backwash and we’ll be able to easily control the depth of the water by adjusting the cap’s position on the tube.Figure 3: Our caps
  3. Parallel Tubes
    1. Having a slope is no use to our lab, so we will arrange our tubes parallel to the floor. Instead of using the slope to control the depth of our water, we will be using our tubes.

24 September 2018 - Revising New Caps

We are in the process of revising new caps.  Our previous caps and nozzle [Figure 1 and Figure 2] were slightly too small, and the nozzle was in the middle when it should’ve been either in the middle or higher up. Our caps were originally designed so we always have a certain amount of water in our tubes. One side was higher than the other [Figure 3 and Figure 4]. The caps shown below, wouldn’t allow this to happen [Figure 1 and Figure 2]. 

Figure 1

Figure 2

11 September 2018 - TENTATIVE Hydroponics Lab & Stabilizer Sketches

I’ve finally finished sketching our lab. I fixed the last journal’s lab sketch, we need two water basins. One for our controls, and the other with salt.

I’ve also been working on the stabilizers, and I have 3 Ideas.

Below is a sketch of what the stabilizers would look like. The stabilizers will slide on to the skeleton of the lab and cradle the tubes in which the plants grow in. In order to keep the stabilizers from sliding around the skeleton, we could put zip ties on both sides of the stabilizers.

The only problem is, I’m not sure if the tubes will slip out of the stabilizers. To counter this, I’ve come up with 2 ideas of how to hold the tube securely.

  1. Line the lower side of the tube with rubber bands, so the tube can’t slip further down.
  2. Make split caps, bound by elastic or rubber bands. This would ensure a tight fit on the tubes.

Purple writing: “can stretch apart; snug fit on caps” (should be corrected to tubes)

5 September 2018 - Hydroponics Research/Plans

Last Friday, I compiled a paper of things we needed to keep in mind as we were building our next Hydroponics Lab. Using the knowledge that I”d gained, I constructed a new possible lab. (below)

Some of my questions have been answered

  1. We won’t need to implement a filtration system
  2. 1 pump and 1 water basin is sufficient
    • on top of that, we can also place the basin below the lab to save space
    • with that being said, we don’t have to draw up a plan for a water basin above the lab

However, we still need to finalize the stabilizers and choose the optimal one.

We have a couple of ideas so far:

  • Last year’s idea ( see May 21’s Stabilizers Journal)
  • A t-joint contraption
  • Stabilizers that slide onto the tubes
    • it’s basically like the stabilizers that we designed last year, except that they slide on
    • below is a really rough sketch, it’s to get an idea

Nicholas also finished modeling the funnel caps for the ends of the tubes (shown in lab sketch above). It is to scale, and ready to be printed out.

27 August 2018 - New Year of Hydroponics

Another year of Hydroponics! In class today, I looked through our server to see where we had left off last year and gauge what we need to work on.

Basically, we need to come up with a new design for our lab. We have/know how we want certain pieces to look like, but we don’t know what we want the overall lab to look like.

Some of my suggestions are

  1. Have 3 tubes.
    • We need one tube as our control and then we could compare two different salinity levels in the other tubes.
  2. We will need to multiply everything by 3
    • We shouldn’t get ahead of ourselves, and simply try to grow our control plant first to make sure we get everything right. However, if we decide to have 3 tubes, we would need 3 of everything
  3. Use a filtration system.
    • If we don’t have a filtration system, we would be wasting a lot of water. I say we implement a filtration system and then readd the nutrients. We’re going to have to add nutrients/salt to our water even if we don’t have a filtering system.

——Hydroponics 2017/2018——

22 May 2018 - Hydroponic's Lab Progress/Recap

Today is my last WISRD class. We are leaving our lab unconstructed, which is probably for the better. Sadie and I will pick up where we left off next year.


21 May 2018 - Stabilizers

As part of our new lab, we plan on placing the tubes on top of our frame. However, we need stabilizers so that they don’t roll off. Below is a sketch of what we want them to look like/function.

The stabilizer will cup and cushion our tubes. We will have some room of empty space below it because the stabilizers will almost form a Y shape. We will be doing some experimenting because we want the tube to be able to detach from the stabilizer.

We do, however, have one problem, we are not sure how to mount it onto the frame.



 11 May 2018 - Growing Plants (Mesh)

Near the beginning of the week, we had a meeting regarding our method for growing our plants. We ultimately decided to have mesh to act as soil for our future plants and build in sensors into our labs.

Since we are growing plants hydroponically, we can’t have soil, so we’ve decided to implement a non-corroding and non- molding mesh.

We would like to include a sensor that will measure the nutrients lost to our plants. That is one of our biggest challenges that we are working on. We want to be able to see the difference in the water in the top reservoir and the water that comes out of the tubes. We want to find out how we can replenish the water with the appropriate nutrients.

We are also hoping to have an interface where we can easily access all our sensors. We are hoping to collaborate with the Arduino team for this.

We created a to-do list:

  1. Test reverse caps
  2. Measure water line (average measurements)
  3. Assemble new caps


7 May 2018 - New Hydroponics Plan

As I’ve mentioned in a previous Journal entry, we have decided to scratch our hydroponics plan and create a new one. There were a couple of problems with our last plan:

  1. The lab was too big, we wouldn’t have a good place to put it.
  2. It would be hard to pump the water from the reservoir to the tubes.
  3. There would be no water flow inside the tubes.

With our new plan, we’ve fixed all of these problems:

  1. Our lab is much smaller now, with only 2 tubes instead of 4.
  2. We would place our reservoir above our tubes, so we don’t need a motor to pump the water into a tube.
  3. We placed our tubes at an angle to achieve a natural water flow. Since the reservoir is now above our tubes, the water simply needs to move down a pipe into our reservoir and then flow down the tube.

Some other changes we’ve made to lab include:

  1. Making the holes further apart. We are only going to have 3 holes in each tube, as opposed to 4. This will ensure that the plants have ample room to grow.
  2. We’ve created caps for the ends of our tubes, see the previous journal entry for more details

There are still some problems with our lab that we need to figure out:

  1. We need to find a way to reuse all the water that comes out of our tube. Our plants will suck the nutrients out of the water as it passes by, so the water that falls into the bottom reservoir won’t be the same as the water we initially put in the top reservoir. We don’t want to waste a lot of water, so we need to find a way to reuse the same water. That is what we’re working on right now.


24 April 2018 - Update

We have completely changed our plans for our lab model, Instead of having 4 tubes where the plants will grow, we will have only two and they will rest at an angle. We plan to have our water reservoir at an angle to keep the water flowing. We will have to create a new drawing of our hydroponics lab. We have also developed caps to fit on the ends of our tubes.

Our AC power supply has arrived and we will go back to testing the current of our NaCl solutions.


We gave the CAD team our measurements and had the caps printed out. The fit was a little tight, so we had to sand it to make the caps fit over the ends of the tubes.


16 March 2018 - NaCl Electric Current

We are currently in the midst of creating a calibration curve for our sodium chlorine based on its electric current. We are learning about the relationship between the different molarities and its current.


27 February 2018 - Finished Copper Sulfate II Calibration Curve

Since our NaCl Calibration hasn’t been working, we decided to test the Spectrometer to make sure it was working properly. To test this, we created a simpler calibration curve using Copper Sulfate II. We measured out 3 solutions with different molarities, as seen in the chart below.
We then made an unknown solution and I had to figure out what the concentration was. I was able to get pretty close to the actual molarity.


13 February 2018 - NaCl Calibration Curve Update

For the past couple of weeks, we have been trying to create a Calibration Curve for our NaCl samples, but have so far been failing. We have tried many times, and have gotten different results every time. When we simply run the absorption of our different samples, we come across a graph like this:

There are several things wrong with this. For one, our sample with the highest absorption is 2.7 moles of NaCl; it should be 3 moles. We have been getting different results every time we run this same experiment. We are unsure if the problem is on our side, or on the spectrometer’s side. Due to this, we are going to be testing out the same experiment but when copper sulfate. We found a video on YouTube from PASCO Spectrometer where they showed how to use Beer’s Law to create a calibration curve and then find the concentration of an unknown solution. We decided to follow their example exactly and see if we get the same results, this way we will know if we are doing something wrong or if something is wrong with the Spectrometer. We have created a new table which we are following and are in the midst of creating our solutions.

Copper Sulfate II

1 mole 0.2 moles 0.14 moles 0.08
1 L 50mL 50mL 50mL
159.6086 grams. 1.595 1.115 0.640


 26 January 2018 - Taking Inventory/What We Need
We have taken inventory of our lab.
As of now, we have
6 blue buckets
1 water reservoir
1 PVC frame
1 Veg- A
1 Veg- B
1 Bud- A
1 Bud- B
1 four cups, or one-liter measuring cup
Several yards of thin plastic tubing
2 Sun grip pulley system
2 eco 296 aqua pumps
1 fan
1 two liter measuring cup
5 FloraFlex with 5 clips to hold the tubing
1 waterproof base
1-meter ruler
1 Great White Mycorrhizae
1 Sunblaze fluorescent light
66 green pods


Things We Need:

Item Dimensions Quantity
Clear piping 39 in L, 3 in Diameter 4
Plastic tray 39 in L, 38 in W, 3 in Depth 1
Reservoir tank 9.5 in L, 19.5 in W, 20 in Depth 8
Structural tubing 38 in L 4
Structural tubing 28 in L 4
Structural tubing 39 in L 4
90 degree tubing connectors TBD, circumference uniform with structural tubing circumference 8
Chock Blocks   8


22 January 2018 - Deconstructing Lab
We are in the process of deconstructing our lab. We have disposed of the gro blocks. We threw them in the trash because they were moldy. One interesting observation we made was that there were roots growing out of the bottom of the blocks. The roots were then squished because they had nowhere to go. We washed the water reservoir. Next class, we are going to wash the pump and large tube. We are unsure if we want to keep the frame of the lab for the future.
Meanwhile, Dani has finished the drawing for our future lab. We are going to grow our plants in tubes. We are also working with Jesse to construct and implement an Arduino lighting system.


19 January 2018 - Beer-Lambert Law

We have determined that in order to better understand hydroponics, we have to learn about the Beer-Lambert Law. What this law basically states is that


9 January 2018 - NaCl Spectrometer & Calibration Curve

We tried to run our finished solutions under a Spectrometer but failed. When we ran the spectrometer, we didn’t see anything. Therefore, we cannot create a Calibration Curve.


 15 December 2017 - Finishing NaCl Solutions

This week, we finished our 9 NaCl solutions, right before winter break. We made 100 mL of each molarity level. We are storing them in jars with pipets and will be waiting for after we return from break to test it out on the Spectrometer.


8 December 2017 - Starting NaCl Solutions

Today, we created 3 of our 9 NaCl solutions. We are making 9 NaCl solutions each with different molarities. We are making solutions for .5, .7, 1, 1.3, 1.7, 2, 2.3, 2.7, and 3 molarity levels. Today we made the .5, .7, and 1 molar solutions. Below is the chart that I created and that we are referring to.

    0.5 Mole 0.7 Mole 1 Mole 1.3 Mole 1.7 Mole 2 Mole 2.3 Mole 2.7 Mole 3 Mole










10/ml water .293 .410 .585 .761 .995 1.05 1.46 1.58 1.76
100/ml 2.93 4.10 5.85 7.61 9.95 10.5 14.6 15.8 17.6


1 December 2017 - New Plants & New Proposal
Over the Thanksgiving Break, I grew two more bean sprouts. We added them to the lab and they seem to be doing well. The plants are going at a good rate. However, we have a new hydroponics lab proposal. We are going to have tubes with water reservoirs on the side. The water will flow from the reservoirs to the tubes to a second reservoir. This way, the plants will be submerged in running water, decreasing the chance of mold. We will be able to see how different salinity levels affect the plants affect the plants at the same time. We are going to drill holes so the plants aren’t limited to the tube. We are planning on using mesh for the plant’s roots to grab on to. We are unsure of what plant to grow, research is being done on the perfect candidate. We will start building our new lab sometime next week.


17 November 2017 - Moldy Plants
We found mold growing in our plants. This is probably due to two factors. Previously, we had thought that the plants had not been getting enough water. We moved the clip that holds the watering hose to the center of the plant, that way the water wouldn’t have to travel through the surrounding indents to finally get to the plant. Another thing we were doing wrong is that we weren’t keeping the lights on the whole time. The plants had very little access to sunlight, so the lights above were supposed to help with that. We now moved the hoses to the rims and are keeping the grow lights on day and night. We are going on a week-long break so no one will be able to supervise the plants. We hope that the plants recuperate. Our tallest plant, Ben, has continued to grow at an astounding rate. His height, however, has reached some newfound complications. His weight is not evenly distributed so he is now tilting to a point of breaking. We, for now, have him with a makeshift stand to prevent him from growing sideways.


14 November 2017 - Making Copper Sulfate Solutions
Today we worked with Alicia and just practiced making solutions and using the spectrometer.


10 November 2017 - Poster Night
Poster Night was a huge success, we bought a couple of plants up and a lot of people got to see them and were interested. A lot of people are interested in our project and asked a lot of question, they are eager to see how the project turns out. As for the big tray, we figured out a solution to our problem. We ended up. We placed our water reservoir underneath our main tray and then attached a pipe from the hole in the tray extending until it is submerged in the water reservoir. This way, we are recycling all the excess water.


03 November 2017 - Moving to Larger Lab

This week, we saw a vast improvement in the growth of our plants. One particular plant, whom we’ve named Ben, has grown extremely tall. As of now, he is 12.7 centimeters tall.

We’ve made the transition between the smaller pods to the larger, permanent pods. We still have not figured out an efficient way to water them. There seems to be a part missing in our tray, there is an oddly placed hole that water leaks out of. We have been watering the plants by hand for now, but will soon need to switch over to using the motor as we have a week-long break coming up. Poster night is coming up, so that is another thing we are preparing for.


27 October 2017 - Update
I was out for most of this week, so not much progress was made on my end. When I did come back, I saw that we had success in sprouting the beans in the smaller pods. We realized that we put the beans in incorrectly so some of the roots were growing outward and thus drying out. We flipped and switched them to the right way. One of our beans has been growing exceptionally well. It has grown pretty tall and green. The other beans are trailing close behind.


20 October 2017 - Germination
We have been trying to successfully germinate the seeds. After that, we will transfer the seedlings into the bigger pods in the hydroponics system. As for now, we are just waiting for the seeds to be ready. I have made some progress on our poster for our WISRD presentation. I have just been collecting information and trying my best to present it aesthetically.


13 October 2017 - Getting Started
Regarding the Hydroponics Lab, we switched the pumps because the other pump wasn’t functioning properly. On top of that, we secured the pipe to the pump with duct tape. We got the bean seeds and all that is left to do is plant them, we’ll do that on Monday. We are still unsure if the seedling holders we have nutrients in them or if we are going to have to add our own nutrients. If our first batch of beans doesn’t grow properly, we’ll add nutrients to it. We are planning on building a trough in the future as it will better mimic a field.


06 October 2017  - Intro

The Hydroponics Lab is well underway.

We were able to clean out the station and organize it as well.

We ran a test to make sure the motor still functioned properly. We determined that the motor has a set flow, so we will, therefore, need to devise a way to ensure that our plants will get sufficient water, not too much or little. We are planning on growing beans and basil when we start.

There was an issue with the pipe that connects to the motor when turned on, the pipe flies off thus spraying water everywhere. We need to tightly secure the pipe to the motor somehow.

* Regarding the GAVRT Telescope, we will be rescheduling the meeting as I wasn’t able to attain the GoToMeeting Information.



Ronald Loren Nye, Visions of Salt 1870-1970
history of salinity and drainage
Alan Murray Paterson, Rivers and Tides 1920-1977
water management policies