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Micro-Hydro Design Project
Client: Robin Pepper
Students: Michael Clarke and Colin Weiler
Instructor: Ian Kilborn
Class: ESET 540
Contact Info Robin: [email protected] Ian: [email protected] Mike: [email protected] Colin: [email protected]
Table of Contents
Title Page ................................................................................................................................................................................. 1
Problem Statement ................................................................................................................................................................. 2
Statement of Work.................................................................................................................................................................. 2
Flow Measurements and Instantaneous Power Calculation .................................................................................................. 3
Analyzing Representative Waterways to Predict Annual Energy Potential of the Dam Site .................................................. 5
Selecting the Right Turbine ..................................................................................................................................................... 7
The “LH1000-Low Head” Turbine ........................................................................................................................................... 8
The “PowerSpout LH / LH Pro” Low Head Turbine ................................................................................................................. 8
Primary System Design - Intake Canal .................................................................................................................................. 10
Alternate System Design - Stand Pipe ................................................................................................................................... 13
Winter Operation .................................................................................................................................................................. 15
LH1000 System Diagram (With Heating) .............................................................................................................................. 17
LH1000 System Diagram (Without Heating) ......................................................................................................................... 17
Increasing Available Head Pressure ...................................................................................................................................... 18
Interesting Micro-Hydro Photos and Links: .......................................................................................................................... 20
Problem Statement
Robin Pepper, Coordinator of Advertising and Interactive Marketing here at St. Lawrence College, would like to know the
feasibility of developing a grid-tied micro-hydro system on a stream adjacent to his home. His is looking for technically
feasible and economically justifiable solutions, as well as predicted financial returns.
Statement of Work
In order to meet the above stated needs of the client, Michael and Colin were required to complete the following tasks:
Through a site visit, obtain measurements required for the calculation of head and flow.
Through research , make a determination of the most suitable turbine type and system design to meet the site
characteristics. Further describe why certain designs and turbine types were not suitable for the site.
Write a detailed description of the proposed system design.
Compile as best as possible a list of materials with associated costs.
Create a 3d model of the proposed system design.
Present at least one alternative system design in lower detail.
Create a suite of Excel tools to assist the client in the following: Accurately measuring the energy potential of
the stream over a year; computing the predicted financial returns; and allow for the comparison of these values
to other representative waterways in Ontario.
The deadline for completion of the tasks described above is to be the second week of December, 2014th.
Flow Measurements and Instantaneous Power Calculation
We visited the dam site in October. Our objective was to take measurements that would allow us to calculate the
potential energy of the stream, at least for the conditions on that day. Determine the potential energy of any waterway
requires the following values:
Speed of the water at time of test.
Cross-Sectional Area of the water at the time of test.
Difference in height between high points and low points of water at the time of test (Head).
Water Speed
To calculate water speed, we performed three tests. We dropped a stick upstream of the dam, and measured the length of time required for it to travel a known distance. The distance was 16 feet, measured and staked out beforehand. This gave us time (s) and distance (ft), and therefore surface velocity (ft/s).
However, not all water is flowing at the same rate. The water at the bottom of the stream is slowed by friction with the ground. Therefore, we applied a factor of 0.80 to determine the actual water velocity. This factor of 80% represents an approximation of what would have been a complicated mathematical calculation using formulas from fluid dynamics.
Test Number Distance travelled Time Surface Velocity
Average Velocity x(0.80)
Test #1 16 ft 20.5 sec 0.78 ft/s 0.62 ft/s
Test #2 16 ft 17.6 sec 0.91 ft/s 0.73 ft/s
Test #3 16 ft 21.8 sec 0.73 ft/s 0.59 ft/s
Overall average velocity of water: 0.65 ft/s
Cross-Sectional Area
The second necessary measurement was that of the cross-sectional area of the stream. This can be thought of the area of a vertical 'slice' of water. To do this, we took upstream depth measurements along the length of the dam, starting from the 'far' bank. Another necessary component to obtaining flow requires the calculation of cross-sectional area of a 'slice' of the water. During our site visit, we took depth measurements along the length of the dam, at set intervals, starting from the 'far' bank.
3D Sketchup Model displaying cross-
sectional area measurement results
In the model, the pink sections represent the cross-sectional area of the water as measured on our site visit. However,
water level rises and falls during the year. The dark red slice therefore represents the additional cross-sectional area of
water during times of very high tide, when the water reaches to the lip of the dam. We present this measurements in
the table below:
Distance from Last Measure Water Depth Cross Sectional Area Inferred 'High-Tide' Cross Sectional Area
2 ft (from bank) 16" 1.33 ft2 6.33 ft2 (+5.0ft2)
1 ft 28" 1.83 ft2 4.33 ft2 (+2.5ft2)
1 ft 32" 2.50 ft2 5.00 ft2 (+2.5ft2)
1 ft 32" 2.67 ft2 5.12 ft2 (+2.5ft2)
1 ft 28" 2.50 ft2 5.00 ft2 (+2.5ft2)
1 ft 24" 2.17 ft2 4.67 ft2 (+2.5ft2)
1 ft 15.5" 1.65 ft2 4.15 ft2 (+2.5ft2)
2 ft 9" 2.04 ft2 7.04 ft2 (+5.0ft2)
2 ft 4" 1.08 ft2 6.08 ft2 (+5.0ft2)
Cross Sectional Area Totals: 17.77 ft2 47.72 ft2
Calculating Water Flow
Once the two quantities of water speed (ft/s) and Cross-Sectional area (ft2) are determined, it becomes possible to
calculate 'Flow'. Flow is a measure of volume over time. Therefore, we perform a simple multiplication:
Flow = Speed * Area Flow = 0.65ft/s * 17.77ft2 Flow = 11.55ft3/s (imperial) [imperial to metric conversion: 11.55 x 0.02832] Flow = 0.33 m3/s (metric)
Water flow was thusly determined to be 0.33 m3/s on the day of measurement. That value will be the baseline for
calculating the instantaneous theoretical power available in the water. We did not use the inferred 'High-Tide' area in
our calculation, as 1) it would result in an over-estimation of available power and 2) we did not observe 'High-Tide'
conditions on the day of our measurements. (Incidentally, calculated flow for 'High-Tide' is 0.88 m3/s)
Measuring 'Head'
Head is a hydrologic term referring to the
difference in height between high water
level and low water level. We measured it
to be 7' 7" on the day.
Converted to metric units:
((7ft * 12in/ft) +7in) * 0.0254m/in =
2.31 m (Head)
Calculating Instantaneous Power
Finally, we now have all the required values to calculate the theoretical instantaneous power available in the water
during time of measurement. Calculated as follows:
Pth = p * q * g * h
Pth = Power Theoretically Available (W) p = Water Density (kg/m3) q = Water flow (m3/s) g = Gravitational Acceleration (m/s2) h = Falling Height; Head (m)
Pth = p * q * g * h
= 1000 (kg/m3) * 0.33 (m
3/s) * 9.81 (m/s
2) * 2.31 (m)
= 7,478 W = 7.48 kW
Therefore, the power available within the water during time of measurement was found to be 7.48 kW's. This value is
perquisite for sizing whatever turbine we hope to install at the site.
Bear in mind, this value only holds true for specific water velocity, area and head values. If any of those values change,
which they most certainly will over the course of a year, the power calculation changes too. This value of 7.48kW's tells
us very little about the actual annual energy generation potential of the dam site. To do THAT, we opted to employ some
creative analytical methods using historical flow data from representative waterways.
Analyzing Representative Waterways to Predict Annual Energy Potential of the Dam Site
The Government of Canada has a depository of historical
hydrometric data from stations monitoring the flow of many
hundreds of different waterways.
Because we have no data for the flow or head characteristics of
our site of the course of an entire year, we can approximate what
they might be by analyzing the data from similar waterways.
How do we select those waterways which might be similar? By
looking at their historical flow values for the month of October,
the only month for which we have data on our site (0.33 m3/s
during time of measurement). If the historical waterway has an
average flow near to 0.33 m3/s in the month of October, it may
display flow characteristics similar to our waterway for the rest of
the year.
From the website, we downloaded monthly flow data (monthly - comma separated value) for the representative
waterways. Therein are lists of average flow measurements for every month of every year the station was operational.
By summing all the "October" average flow values, and dividing by the number of October flow measurements, we
obtain an 'average-of-the-averages' of flow for that waterway; in the month of October; over the 'lifetime' of that
monitoring station.
If that number is close to 0.33 m3/s, we can make the following loose assumption: "Since the October flow of this
historical waterway is near to the October flow of the dam site, perhaps the same is true for the other months".
Source: http://wateroffice.ec.gc.ca/
We then began compiling the 'average-of-the-averages' of flow for each month from those waterways that seemed to
offer realistic comparisons. The data from those representative waterways are in the accompanying Excel file:
Analyzing the data offers some insight.
Generally, flow appears to be low in January,
spike during the spring thaw, dip during
summer, rise during fall before dropping in
winter.
Flow data from Site#1 (Hayden Brook) and
Site #4 (Whitesand River) appear to offer
under-estimations compared to our 0.33
m3/s flow data point.
Flow data from Site#5 (Milhaven Creek) and
Site #6 (Depot Creek) appear to offer over-
estimations compared to our 0.33 m3/s flow
data point.
Flow data from Site#2 (Bennet Creek) and
Site #3 (Nolin Creek) appear to offer
reasonable estimates compared to our 0.33
m3/s flow data point.
Therefore, flow data from either Bennet
Creek or Nolin Creek offer the most
reasonable estimate for expected flow at the
dam site.
Bear in mind however, that these
comparisons are only valid if the flow measurements we took at the dam site were accurate, which they may not be.
We've detailed our measurement procedures, and provided the accompanying Excel spreadsheet, for the explicit
purpose of empowering the client to perform his own measurements of the dam site over a years time, obsolescing the
need for comparison with representative waterways.
Selecting the Right Turbine
The two most important factors that determine which type of turbine is most applicable to a hydropower project are
Head and Flow. There are many different turbine designs to meet the needs of each hydro-power site.
Recall that during our site visit, we measured 2.31 m of head at 0.33 m3/sec of water flow.
Considering the chart above, we can see the flow and
head characteristics of the dam site lies within the
bounds of a “Vertical shaft – exposed type” turbine. Also
to note is that the characteristics of our stream suggest
turbine power of between the 2.5kW and 10kW (black
diagonal lines), at approximately the 4kW mark.
Considering the chart to the right, we can see that a
“Kaplan” type turbine would be our choice.
Therefore, given the characteristics of the dam site, the
optimal turbine is a “Vertical Shaft – Exposed Type”
turbine of “Kaplan” design, with power output of
approximately 4kW.
After intense investigation, we were able to find two
turbines that met these criteria, both from Canadian distributors: the LH1000 and the PowerSpout LH / LH Pro. It was a
difficult search, as most turbines are designed for at minimum 5-10m head pressure, and would absolutely not function
under the 2.3m head we have available. These two Low Head turbines are described in the next section.
Source: Turbine-Generators Blog
Source: HydroNI
The “LH1000-Low Head” Turbine
A company in New Brunswick called “Energy Systems and Design Ltd.” offers a 1.0kW vertical-shaft
turbine called the “LH1000”, pictured to the right. It is designed to operate within a head range of
between 2 and 10 feet. Recall that we had measured the head of our stream to be 7’7”. Consider the
following chart:
To determine the exact expected power output at the head of our stream, we performed the following interpolation:
(grey cells are calculated values)
Therefore, we would expect a single LH1000 turbine to be able to
produce 661W at our stream. Such power output is hardly
impressive, and would likely not be sufficient for financial
viability. However, consider the following:
From data collected on our site visit, we had calculated October flow
to be 0.33m3/s. Converted to imperial units, that is 5231 gallons per
minute (GPM). A single LH1000 turbine produces 661 Watts with
813 gallons per minute of water, much less than total available flow
from the stream. This allows for the option to install several turbines
to harness as close as possible to the maximum possible flow:
5231 GPM total flow / 813 GPM per turbine = 6.43 ~= 6 turbines.
Therefore, flow potential of the stream can support up to 6 LH1000
turbines. That would yield:
661 Watts/turbine * 6 turbines = 3966 Watts = 4.0kW's.
Therefore, 6 turbines have the combined power potential of
4.0kW's.
It is our suspicion that a system with just a single turbine of 0.6kW would not be financially viable. The fixed costs
associated with electrical, regulatory and MicroFIT contract issues are the same, regardless of system size. However,
with a combined system power of 4.0kW, we may see predicted revenue great enough to offset these fixed costs and
offer a return sizable enough to justify the project.
The “PowerSpout LH / LH Pro” Low Head Turbine
An alternative to the LH1000 turbine is the PowerSpout LH / LH Pro Turbine. It is fundamentally the same design as the
LH1000, with perhaps more robust construction being the most evident difference.
Head (ft) Flow Volume (GPM) Watts(approx.)
7 775 585
7’7” 813 661
8 840 715
From LH1000 Manual, Page 5.
The PowerSpout website offers an online calculator to help predict the power output of one (or several) turbines given
set site conditions. Below are the results generated from two such calculation reports:
Intake Channel Design Holding tank / Stand Pipe Design Reference #: LH178-A40AB4C8 Reference #: LH177-47FB07E6
Reference Link: Link to Results Reference Link: Link to Results
Flume Length: 6.0 m Pipe Length: 6.0 m
Flume Fall: 2.3 m Pipe Fall: 2.0 m
Flume Material: Wood Pipe Material: Drawn Plastic (PVC)
Flume Width/Height: 0.4m / 0.4m Pipe Capacity: 455 lps
# of Turbines: 6 # of Turbines: 6
Operating RPM: 1044 Operating RPM: 1044
No-Load RPM: 1565 No-Load RPM: 1565
Used/Available Flow: 228 lps / 330 lps Used/Available Flow: 228 lps / 330 lps
Output Voltage: 156 V Output Voltage: 156 V
No-Load Voltage: 312V No-Load Voltage: 312 V
Actual Load Voltage: 140V Actual Load Voltage: 140 V
AC Cable Efficiency: 90% AC Cable Efficiency: 90
Cable AWG / size: 11 AWG; 3.8mm2 Cable AWG / size: 11 AWG; 3.8mm2
AC Amperage: 16.7 A AC Amperage: 16.7 A
Output per PowerSpout: 433W Output per PowerSpout: 433W
Total PowerSpout Output: 2.60kW Total PowerSpout Output: 2.60kW
Total AC Power Output: 2.34kW Total AC Power Output: 2.34kW
Recall that the LH1000 turbine was calculated to produce 661 Watts for total output of 4.0kW. This compares very
favourably to the calculated 433 Watts per PowerSpout turbine and 2.60kW total output. This suggests that the LH1000
turbine would be the better choice for our system design.
Primary System Design - Intake Canal
We propose a system of the following general design:
Water is drawn from the pre-existing water bypass, flowing into an intake canal. This wooden canal carries water with
no change in height to a trough downstream of the dam. Affixed through this downstream trough are the six turbines.
As water flows through the guide vanes of each turbine, vortices are created, much like water draining down a sink. For
each turbine, this flow plummets through runner blades down a draft tube, turning the generator shaft.
Consider the following picture from the LH1000 Manual detailing the design of a system for use with this turbine:
Intake Canal Design
System Design using the LH1000 Turbine
The "intake filter" can be a metal screen of some sort, either
vertical or angled away from flow, between the water directly
upstream of the dam and the water flowing through the bypass
basin. This has the effect of filtering out sticks and leaves from the
intake canal.
The purpose for a "settling basin" is to provide a small
body of secondary water where dirt, silt and small
debris can collect and settle to the bottom rather than
continue through the canal. The existing dam provides
that beautifully though the existing bypass basin.
Obviously, the branches and detritus that has
collected here would first have to be cleared out. It
might also be necessary to dig out the basin,
increasing its depth and water capacity to match the
rest of the upstream dam.
From the bypass basin, water flows to the intake canal
through a sluice gate. This wooden (or metal) gate
gives control over the amount of flow allowed to
proceed through the canal, and can be closed entirely
to facilitate turbine cleaning and maintenance. An
secondary metal filter here is also an option.
Intake Filter(s)
Sluice Gate & Intake Canal
Bypass/Settling Basin
Flow continues through the intake canal to form vortices around each of the turbine guide vanes.
The water then falls through the draft tube of each turbine, turning the runner blades and engaging the generator.
A convenient patch of flat ground located to the 'left' (looking downstream) of the dam would be an ideal place to
mount the DC-to-AC inverter, as well as any other necessary electrical equipment.
Intake Canal & Turbine Trough
The LH1000 Turbine with Draft Tube
Water Vortex
Through Guide Vanes
Flat Ground for Inverter Mount
Alternate System Design - Stand Pipe
An alternative design to the intake canal is what can be called the "Stand Pipe" design, as follows:
Water is piped from the bypass basin to a
plywood holding tank downstream of the dam.
The water rises within the tank, attempting to
match the water level upstream. The six turbines
are affixed within the tank, with their draft tubes
protruding out the bottom of the tank. As water
rises in the tank, it reaches a point above the
guide vanes of the turbines. Water vortices are
created as this water spills over the 'lip' of the
turbines. Flow proceeds through the runner
blades and down the draft tubes, spinning the
generator shafts.
When first researching this design, it took some
thought to understand how it could produce any
considerable power whatsoever. While at first
glance it may seem an unconventional design, it
can achieve the same head pressure, and thus
power output, of the intake canal design.
Stand Pipe Design
HomePower.com Stand Pipe Design
(Issue 122, Page 53)
Several factors would influence whether an intake canal or standpipe design would be
preferable for this project:
One disadvantage to the stand pipe design is the requirement for penstock piping.
Such piping would most likely be PVC, large in diameter and probably costly. Luckily
though, the required run length from bypass basin to holding tank is quite short.
A significant consideration is how best to deal with the coldest winter months. Given
that water held within a standpipe would be mostly static, it would definitely freeze
during the winter. It might be necessary then to install heaters and insulation within
the standpipe, increasing capital and running costs.
The visual esthetics of each design are very different. If it is the intension of the client
to emphasis an authentic, rustic look, it might be preferable to consider the intake
canal design. It avoids the need for garishly modern PVC piping. It is of course the
client who must make a judgment as to how the preceding consideration are to be
weighted when choosing the design.
HomePower.com Stand Pipe
Design (Issue 122, Page 56)
Water Flow Through the Stand Pipe Design
Winter Operation
If our objective is to maximize the generation of any potential hydro installation, it becomes necessary to consider
winter operation. From an email exchange with the client, it was revealed that from the end of December through mid-
April, the water surface upstream of the dam freezes over, but substantial liquid water remains flowing underneath. This
sparks the possibility of including heating elements in our design that would upstream ice enough to allow year-round
operation. We performed a cost analysis using the accompanying spreadsheet to consider this possibility.
Using the "Nolin Creek" example for the drop-down
menu on the "Annual Energy Calculator" page, we
considered year round operation with electric
heating elements. Such a scenario adds additional
capital, annual and replacement costs, as indicated
below. We assumed that the increased wear on the
turbines from all-season operation be necessitate
their replacement twice during the system service
life, first at 7 years, then again at 14 years.
Fixed Costs of Heating Element(s):
Annual Costs of Heating Element(s):
Replacement Costs Due to Winter Operation:
It can be seen that even after increased capital,
electric heating and additional turbine
replacement cost, the model predicts an
$89,602 revenue over the 20 year system
lifetime. This is a considerable sum, and speaks
to the idea that it may be worthwhile to invest
in a system capable of year-round operation.
System Shutdown During Winter
An alternative to year-round operation would simply be to remove the turbines from the system come December, and
store them for the winter. This would negate the need for heating altogether, reducing capital and running costs, and
decrease wear-and-tear on the turbines. Of course, all potential revenue for those four months would be lost.
Using the "Winter Scenario" example for the
drop-down menu on the "Annual Energy
Calculator" page, we considered that possibility.
Adjacent is a graph showing the scenario of
100% generation during the summer/spring/fall
months, and 0% generation during the winter
months. Notice in the cells below how the
removal of heating elements reduces fixed,
annual and replacement costs:
Fixed Costs:
Annual Costs:
Replacement Costs with no Winter Operation:
Even with reduced fixed, annual and
replacement costs, the model predicts an
accrued revenue sizably lower than the design
that runs during winter. The loss in generation
from those four months has a significant effect
on the bottom line. This value for predicted
revenue is approximately 20% lower than the
year-round value, and speaks to the point that it
may be worth the cost, and possible
aggravation, to have the system run year round.
LH1000 System Diagram (With Heating)
kWh Meter(To/ From
Grid)
Fused AC DisconnectMini AC Panel
(120VAC/240VAC to
Heating Load)
kWh Meter(MicroFit – Hydro
Generation)
Fused DC DisconnectCharge
Controller
Outback FLEXmax 80
Outback Radian GS4048A
Inverter
In: Up to 150VDCOut: 48VDC@80ADC
In: 48VDC@80ADC
Out: [email protected]
Out: 12/24/48/120 VDC @ 4.0VA max
6x LH1000 Turbines
Heating Element(s)
(120/240VAC)
Relay Board(For Heat
Element(s))
Temperature Controller
with Sensors?12
VD
C A
uxi
liary
48VDC@80ADC
48VDC@80ADC
240V
AC
@16
.7A
AC
12VDC
LH1000 System Diagram (Without Heating)
To Grid
Fused AC Disconnect
kWh Meter(MicroFit – Hydro
Generation)
Fused DC DisconnectCharge
Controller
Outback FLEXmax 80
Outback Radian GS4048A
Inverter
In: Up to 150VDCOut: 48VDC@80ADC
In: 48VDC@80ADC
Out: [email protected]
Out: 12/24/48/120 VDC @ 4.0VA max
6x LH1000 Turbines
48VDC@80ADC
48VDC@80ADC24
0VA
C@
16.7
AA
C
Increasing Available Head Pressure
We have compiled this report under the assumption that the available head was from immediately upstream of the dam
to immediately downstream. The advantage there is the requirement for little (if any) penstock piping. However, there
may exist the opportunity to increase the available head by drawing from further upstream. This would of course
require that penstock piping be run to the new source, but the increase in available head may make that financial
justifiable. Consider this picture:
It was taken approximately 20 meters upstream of the dam. We can see at least 1 meter of available head here, possibly
more. We did not venture further upstream, but it is safe to assume that the water level would be even higher around
the bend. It is not uncommon for a hydro station to in-take water dozens, if not 100's of meters from the generator(s).
It is conceivable that greater financial return could be accrued by in-taking water from further upstream and piping it to
the generator(s) downstream of the dam. Such calculations are beyond the scope of our investigation, but we present it
for the interest of the client. Below is a simple diagram describing the procedure to calculate available head upstream:
Measuring Uphill
1. Height of level is head for each leg.
2. Repeat multiple legs from turbine location
to intake location.
3. Multiply the height of level times the
number of legs.
Source: Xinda Green Energy
Documentation, Manuals, Spec-sheets and Catalogues
LH1000 Turbine Description
LH1000 Manual
LH1000 Bearings and Assembly
LH1000 Installation
'Energy Systems and Design Ltd.' Price List
PowerSpout LH/LH Pro Installation Manual
PowerSpout LH/LH Pro Manual Supplement
PowerSpout LH/LH Pro System Design
PowerSpout LH/LH Pro Price List
PowerSpout LH/ LH Pro Advanced Calculator
PowerSpout LH/LH Pro Other Information (Left side of screen)
PowerPal Low Head Model Info
PowerPal Low Head Manual
Major Component Make & Model Specs Charge Controller Outback FLEXmax 80 Steady 48Vdc @ 80A output= 4kW max output.
DC-to-AC Inverter Outback Radian GS4048A Input = 48VDC@80ADC. Output = [email protected].
DC Disconnect w/Fuse MNDC Encl. / MNEP Fuse Fuse Rating: 150VDC @ 100ADC, 80ADC available. 6x Hydro Turbines LH1000 Suggested 48VDC Model, 12/24/120/240 available
AC Disconnect w/Fuse GE - TG3221R 30A, 240VAC Fusible Outdoor Disconnect Switch
The LH1000 Turbine is available from Energy
Systems and Design Ltd:
Website: microhydropower.com
Email: [email protected]
Youtube Page: ESDhydro
The PowerSpout turbine was
created by EcoInnovation, a
New Zealand company. They
only provide telephone
support to existing customer.
Products can only be
purchased through their LH/LH
Pro distributors:
DNM Solar
(Ontario) Webster Solar (BC)
Riverside Energy
Systems (BC?)
Topline Power
Systems (Manitoba)
The PowerPal Turbine is manufactured by 'Asian Phoenix
Resources Ltd', located in Victoria, BC.
Website: powerpal.com
Email: [email protected]
Youtube Page: ESDhydro
Interesting Micro-Hydro Photos and Links:
Source: MicroHydroPower.com
Source: MicroHydroPower.com
Source: PowerPal.co.uk
Source: PowerSpout.com
Source: MicroHydroPower.com
http://www.microhydropower.com/Articles/WaterRites.pdf
http://www.level.org.nz/energy/renewable-electricity-generation/micro-hydro-systems/
http://www.homepower.com/microhydro-power/equipment-products
http://www.homepower.com/articles/microhydro-power/equipment-products/hydro-electric-turbine-buyers-guide
http://www.homepower.com/microhydro-power
http://www.homepower.com/articles/microhydro-power/equipment-products/microhydro-electric-systems-simplified
http://www.homepower.ca/dc_hydro.htm
