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CCAT greenhouse rainwater catchment

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Engr305 Appropriate Technology page in progress
This page is a project in progress by students in Engr305 Appropriate Technology. Please do not make edits unless you are a member of the team working on this page, but feel free to make comments on the discussion page. Check back for the finished version on May 23, 2019.


Outside CCAT sits a sloping glass greenhouse. Many changes have occurred in and around the structure during its time at the Campus Center for Appropriate Technology including separation from the main building, construction of a new wall using beach grass as insulation, and a floor reconstruction that's occurring concurrently with our project to build a rainwater catchment system for the greenhouse. CCAT wanted a rainwater catchment system to be built off the greenhouse to catch the rain that would just run down the building and into the ground beneath below. The water captured from the rain will ensure that the plant life at CCAT will be adequately watered when necessary.

The CCAT Greenhouse as of February 21st 2019

The CCAT Greenhouse when facing North West
The CCAT Greenhouse when facing East
The CCAT Greenhouse when facing West

Problem Statement & Criteria

The greenhouse at the Campus Center for Appropriate Technology doesn't have a renewable system to ensure the flourishing of the plants inside. The objective of this project is to build a rainwater catchment system for the greenhouse at CCAT to employ the use of our local weather patterns to water the plants within and outside of the greenhouse. With this renewable source CCAT can reduce their carbon footprint and create a sustainable resource to utilize.

Below is the criteria for the greenhouse rainwater catchment system. The criteria is scaled on a 0-10 high.

Criteria Constraints Weight
Functionality System is expected to run efficiently and effectively
Safety Must be in a secure location where it is easily accessible, also must be out of walkways, doorways, and head space
Aesthetics Must be pleasing to look at and enhance the CCAT environment
Budget Project will not exceed team budget
Durability Must be compatible with structure
Adaptable/Maintenance The structure should be able to be adjusted and mended
Accessibility Filtered rainwater should be easily accessible
Pairability Repair greenhouse cracks
Simplicity Weight should be minimal
Purpose Successfully captures and stores rainwater, educate, and be used for solar shower

Literary Review

This Literature Review will cover aspects of our greenhouse rainwater catchment at CCAT. Including, the climate for the area, filtration types to use, CCAT background, and overall design of rainwater catchments.


This project takes place at CCAT located on the campus of Humboldt State University in Arcata, Californa. Arcata receives about 46 inches of annual average rainfall with a annual average temperature of about 53 degrees Fahrenheit. The city recieves its most rain during the months of November,December, January, and February. An average year in Arcata receives 175 days of sun and on average, 77 days of precipitation.

CCAT Greenhouse

The CCAT greenhouse is located outside of the CCAT building in Arcata, California at Humboldt State University. The greenhouse is constructed of a Beach Grass Clay Slip Wall and a Sturdi-Built prefabricated greenhouse structure. The frame is made of redwood, which is resistant to decay. Preventing decay in a greenhouse structure should be cheap, effective, and non-toxic to plants and animals. The highest recommended solution against wood rot is redwood stain. With the high amount of rainfall that is present in Humboldt County, it is important to ensure the structure is secure. During the Summer the greenhouse requires additional water. In addition to the greenhouse, water is needed to care for surrounding plants and crops. Agriculture is the largest consumer of freshwater. By cutting down the overall water needs for CCAT's agriculture and greenhouse, it can become a high opportunity for a positive environmental impact.

Rainwater Catchment Design

Rainwater design has been worked with for millennia. Ancient civilizations in modern day India and Israel are recorded using catchment methods as early as 3000 BC and later on the Romans developed vast systems of aqueducts, gardens, and pools all fed by rainwater. Since then rainwater catchment has gone into and out of style many times as other technologies developed, but it remains the most reliable and renewable way of attaining access to water.

There is no one way to catch rainwater and design varies depending on many different variables including location, weather patterns, end usage, community utilization, etc.

Catchment design can be broadly categorized into active and passive systems, where active is a system that is built and maintained through human activity and passive is a system mostly in place in the environment that is initially worked on and then maintained by humans. We'll focus on active systems as the project we are working on will fall into that category. In active systems there are some fundamental components.

1. Catchment Surface - Where the rain is falling

2. Conveyance - Transports water from catchment surface to end use

3. Screens - Filters out debris

4. First Flush - Diverts initial most dirty water

5. Storage - Holds water til later use

6. Purification - Cleans water for desired use

7. End Use - Gives the system purpose!

For each of these components there are different materials and technologies you can use.

The main parameters for these systems are rainfall, catchment area, collection efficiency, tank volume and water demand. Systems should be tailored specifically to the community they're serving, so a good place to start you design process is on the ground with the people who will be using it.

Water Filtration Systems for Purifying Rainwater Catchment Systems

1. To Catch the Rain

Filtration basics

Water Filtration is essential to the end use if for human consumption, however, many uses do not require filtration like the first flush or plant use. Filtration concerns

  • Unfiltered Rainwater is not to be to be ingested by humans. Different treatment methods effect different pathogens. Many purification treatments are used in combination.

Types of Filtration

Common filtration materials include Canister filters, Activated carbon filters, Ceramic Filters, Hollow fiber membrane filters,Slow-sand filters, Bioremediation, SoDis, Solar pasteurization, Solar distillation, Boiling, Reverse Osmosis, UV, Chorination, and Electrochlorination.

Designing interpretive materials

According to To Catch the Rain,interpretive materials for rainwater filtration should include a filter, sometimes a structure to hold the filter, and a connecting storage and conveyance point.

2. Rainwater treatment in airports using slow sand filtration followed by chlorination: Efficiency and costs

Filtration basics

Rainwater catchment can be highly valuable as for non-potable settings such as airport complexes. Cost efficient, this method is valuable in this setting because of the large catching surfaces. Based out of a mid-sized airport in Brazil, this system studied the performance of slow sand filtration by chlorination and cost effectiveness. Overall, this project resulted in 60% cost efficiency compared to current water supply per cubic meter, ultimately providing chemical and biological-free water.

Filtration concerns

Not labeled for human consumption

Types of Filtration

Slow Sand filter following Chlorination filtration.


According to the Resources, Conservation, and Recycling book, 70% of the company’s non-potable water can be accounted for by this rainwater catchment and treatment system.

3. Effective removal of microbial contamination from harvested rainwater using a simple point of use filtration and UV-disinfection device

Filtration basics

Focusing towards utilizing of harvested rainwater for alternative water source on privately-owned cisterns in Arizona, this treatment uses Point of Use (POU) and UV filtration.

Filtration concerns

Originally, the untreated water contained levels of lead, Enterococci and E. coli, POC filtration sufficiently cleaned the rainwater of most contaminates.


In this section, we will be going over the construction of the the project. This will include some of the design stage, the prototypes that were created and though of, construction of the rainwater catchment system, and finally the final results.


Task Description Proposed Date Actual Date
Scope out project area Get a feel for the space, start to come up with prototype ideas February 26th, 2019 March 5th, 2019
Create prototypes Come up with different routes to take on this project, focus on placement of rainwater system components, design for desire and function March 12th, 2019 March 12th, 2019
Meet with CCAT Talk with them about their goals of the rainwater catchment and discover end goals of rainwater March 26th, 2019 March 27th, 2019
Weekly CCAT meetings Attend weekly CCAT meetings to discuss project progress, improvements, and feedback Weekly Weekly
Start to gather materials Look through supplies at CCAT and find things that we can use for the catchment system March 12th, 2019 March 27th, 2019
Meet with Risk Management Lonny ended up becoming the spokesperson when it came to facilities management and met with them on our behalf April 1st, 2019 Varies
Start construction Break ground on our project, brought in river rocks March 26th, 2019 April 4th, 2019
Continue construction Continue to build rainwater catchment system, keep adding to system and striving for excellence April 2nd, 2019 April 5th, 2019
Meeting with Lonny Have Lonny come look at the progress of the project and provide any feedback, feedback included getting rid of the wood pallet that the storage tanks were on April 9th, 2019 April 9th, 2019
Catch up with other groups Get updates and progress reports, help each other if possible and learn from one another to improve everyone's projects as much as possible to ensure a positive working/learning environment April 16th, 2019 May 1st, 2019
Finish presentation and Video Ensure that the video shows all attributes of the system and clearly communicates the project, the goal, and the design April 30th, 2019 May 13th, 2019
Work on Appropedia final draft Make sure formatting is clean, clear, and to the point April 30th, 2019 May 13th, 2019
Wrap-up construction and finishing touches Make sure that the project works and is completed to the best of the teams abilities May 7th, 2019 May 15th, 2019


Quantity Material Source Cost ($) Total ($)
6 PVC pipe Ace 7.00 42.60
1 Storage Tank, 50 Gal Resale store 33.00 33.00
1 Filter Resale store 5.00 5.00
2 Gutter Resale store 4.00 8.60
1 Silicon Hamanaka Painting Donation Donation
1 Nails Ace 3.70 3.70
1 Aesthetics TBD 50.00 50.00
Total Cost $223.70


Kinkade-Levario, Heather Design for Water: Rainwater Harvesting, Stormwater Catchment, and Alternate Water Reuse New Society Publishers, Jun 1, 2007

Grafman, Lonny To Catch The Rain Arcata. Humboldt State University Press, 2017

Mun, J.S. "Design and operational parameters of a rooftop rainwater harvesting system: Definition, sensitivity and verification" Eleviser Volume 93, Issue 1 (2012)