**4.1.4.3 Manifold line**

Manifolds placed under soil are smaller-scale pipes as compared to sub main pipes as other pipes. Manifolds are placed vertical to parcel edges and maintain laterals. Manifolds mostly consist of HDPE pipes.

#### **4.1.4.4 Lateral line**

They are the smallest scale pipes within system. Lateral pipes are responsible for transmitting water from manifold pipes to sprinkler pipes. Laterals are placed under soil in landscape irrigation. All pipes in system are tied to each other by help of connectors.

#### **4.1.5 Sprinkler heads**

The most important parts of sprinkler irrigation system are certainly sprinkler heads. Sprinkler heads are placed at certain intervals over laterals. As well as sprinkler heads is placed on a riser over lateral, they are generally embedded underground in landscape irrigation and known as pop up. Pop up heads do irrigation, moving over soil surface when water is given in system. There is two type of sprinkler heads divided as spray and rotor. Spray heads irrigating without turning are used for confined space (Figure 4). Wetting dimensions of them are 2-4.5 m and working pressures are 1-3 bar (Orta, 2009). Spray heads throw water in higher amounts in more narrow space as compared to rotor. Rotors are used in wider areas with lower precipitation rate (Figure 5.). Rotor type heads are generally used in landscape irrigation. Unit price of spray heads are lower as compared to price of rotor heads but facility costs of sprays are higher as compared to the ones of rotors. Factors such as soil infiltration rate, type of plant, wind conditions, limitations of pressure, demands of owner of system should be taken into account in choice of heads. Also, lowest flow of system, low operating pressure and widest spacing of sprinkler head are considered while making a choice between heads which can meet necessary requirement of water in system. Technical properties related to pop up head are presented in schedule (Table 1).

#### **4.1.6 Water distribution in sprinkler irrigation method**

Water throws towards to air at a certain angle in sprinkler irrigation. As a result of this, head as being in center, causes a circular area to be wetted. This area is called as wetting area of sprinkler head. Big water grains drop around head during irrigation and size of water grains dropping over soil get smaller as head goes far. Each head constitute a water distribution depending on dimension of orifices over which each head is equipped and operating pressure (Melby. 1995). In case of head pressure`s decreasing under optimum

Submain pipes are the same type of pipes with main pipes. The highest cost in irrigation systems is cost concerning pipes and mainly main pipes. In choosing of irrigation pipes, pipes which have minimum capacity to meet requirements of flow in system should be chosen. By purpose of water distribution to be provided in different regions in major irrigation systems, dimensions of pipes are changed from a point which is broken into pieces from main pipes and by this way, disposals can be provided, using pipes which carry

Manifolds placed under soil are smaller-scale pipes as compared to sub main pipes as other pipes. Manifolds are placed vertical to parcel edges and maintain laterals. Manifolds mostly

They are the smallest scale pipes within system. Lateral pipes are responsible for transmitting water from manifold pipes to sprinkler pipes. Laterals are placed under soil in

The most important parts of sprinkler irrigation system are certainly sprinkler heads. Sprinkler heads are placed at certain intervals over laterals. As well as sprinkler heads is placed on a riser over lateral, they are generally embedded underground in landscape irrigation and known as pop up. Pop up heads do irrigation, moving over soil surface when water is given in system. There is two type of sprinkler heads divided as spray and rotor. Spray heads irrigating without turning are used for confined space (Figure 4). Wetting dimensions of them are 2-4.5 m and working pressures are 1-3 bar (Orta, 2009). Spray heads throw water in higher amounts in more narrow space as compared to rotor. Rotors are used in wider areas with lower precipitation rate (Figure 5.). Rotor type heads are generally used in landscape irrigation. Unit price of spray heads are lower as compared to price of rotor heads but facility costs of sprays are higher as compared to the ones of rotors. Factors such as soil infiltration rate, type of plant, wind conditions, limitations of pressure, demands of owner of system should be taken into account in choice of heads. Also, lowest flow of system, low operating pressure and widest spacing of sprinkler head are considered while making a choice between heads which can meet necessary requirement of water in system.

landscape irrigation. All pipes in system are tied to each other by help of connectors.

Technical properties related to pop up head are presented in schedule (Table 1).

Water throws towards to air at a certain angle in sprinkler irrigation. As a result of this, head as being in center, causes a circular area to be wetted. This area is called as wetting area of sprinkler head. Big water grains drop around head during irrigation and size of water grains dropping over soil get smaller as head goes far. Each head constitute a water distribution depending on dimension of orifices over which each head is equipped and operating pressure (Melby. 1995). In case of head pressure`s decreasing under optimum

**4.1.6 Water distribution in sprinkler irrigation method** 

as need. These pipes transmit water taken from main pipes to manifolds.

**4.1.4.2 Submain line** 

**4.1.4.3 Manifold line** 

consist of HDPE pipes.

**4.1.5 Sprinkler heads** 

**4.1.4.4 Lateral line** 

pressure or increasing it causes deformation of water distribution in Figure 6. Changes of water distribution under different pressures are given Figure 6.

Fig. 4. Samples of using spray

Fig. 5. Samples of using Rotor

It is not possible to provide uniform distribution in irrigating area by singular heads in sprinkler irrigation system. Uniform distribution is obtained by using more than one heads. Factors which affect water distribution are the sprinkler nozzle, operating pressure, flow rate, speed & uniformity of rotation, spacing of the sprinklers, pattern of the sprinkler grid and wind. What is required to be done after choice of appropriate head by purpose of providing uniform distribution is defining sprinkler pattern and sprinkler space. Heads are commonly lay out in shapes of triangle, square and rectangular. Triangular shape is used most commonly in landscape irrigation. In choice of triangular shape better water distribution is obtained in areas having equilateral triangle as compared to square shape. Water disposal is obtained in decreasing waste water due to its water distribution pattern `s being better as compared to square shape. Head in less numbers are used since sprinkler heads are placed to more distant area in triangular shape. Triangular shape presents better performance in irregular areas as compared to square shape (Melby. 1995). Another factor is distance between heads. For a good water distribution head intervals on lateral shouldn`t be more than 50% of dimension of wetted area. Also lateral intervals affect water distribution.

Irrigation 311

Since sprinkler heads make irrigation by throw water towards to air at a certain angle they are highly affected from windy air conditions. By aiming at obtaining the best distribution in windy conditions by irrigation system a number of arrangements in choosing of sprinkler are required (Barrett et. al. 2003). These arrangements may help to perform a better distribution since water which is sprinkled from less wetting scale heads drop closer area and their interaction with contact of wind is less in areas which are exposed to wind excessively. Having the smallest throw angle should be used. Optimal throw angle is 32º

sprinkler irrigation under normal circumstances. However it is required to reduce this angle in windy conditions. Adjusting throw angle as 22-27o in areas where wind speed is higher than 2.6 m/sec shall give better results. However heads are required to be placed in a closer area for corresponding water distribution since fire distance is decreased in this case. Also

Water distribution uniformity is a parameter that questions situation of hydration of irrigated area with corresponding amount of water. This parameter is one of the main factors which is useful for decreasing system costs thanks to consume of less electric, water, fertilizer and pesticide in connection with its irrigation performance. Different parameters are used by purpose of determining uniformity of water distribution. Parameters which are commonly used are sprinkler uniformity Christiansen's coefficient of uniformity (CU),

Distribution uniformity is one of the methods which is preferred in determining uniformity in irrigated area. In this method, amount of precipitation is measured by means of caps placed in irrigated area. Then uniformity value is determined by estimating average catch amount belong to quarter which has least water with average catch amount of irrigated area (ASCE.1978). For example, 5 caps Where has the lowest catch amount represent average catch in the low quartile in a test where there are 20 measurement caps (Walker and Skogerboe 1987). Distribution uniformity (DU) should be greater than 75% and if greater than 85% is excellent and acceptable for any sprinkler irrigation. The value of Distribution

DU=(MQl/M)\*100 (7)

Distribution uniformity should be at least 70% in rotor heads and 50% in spray heads. As

Christiansen Coefficient of Uniformity is used commonly in irrigation sector. Christiansen (1941) developed a formula which depends on average value of irrigation water amount and standard deviation value which are measured through caps placed in irrigated area. CU is

laterals should be placed vertical to wind direction.

**4.1.6.1 Distribution uniformity (DU)** 

DU: Distribution uniformity, %

Where.

Distribution Uniformity (DU) and Scheduling coefficient (SC).

Uniformity coefficient is calculated using the following expression.

MQl: Average collected volume of lower quarter of catch cans, l

being different from DU, CU and SC parameters can be determined.

M: Average collected volume of all catch cans, l

**4.1.7 Christiansen coefficient of uniformity** 

calculated by means of formula below.

for

Lateral intervals in line of main pipes shouldn`t be over 65% of wetting area. Technical charts presented by producing company are available for each head. In these charts head flows and wetting area in different orifice dimensions and operating pressure are stated. These charts are used in choice of appropriate heads in irrigation area (Yldrm. 2008).


Table 1. Technical schedule related to pop up head

Fig. 6. Water distribution histogram obtained under different operating pressures (Gungor et. al. 2010).

Lateral intervals in line of main pipes shouldn`t be over 65% of wetting area. Technical charts presented by producing company are available for each head. In these charts head flows and wetting area in different orifice dimensions and operating pressure are stated. These charts are used in choice of appropriate heads in irrigation area (Yldrm. 2008).

> **Flow (l/min)**

1.4 2.1 6.51 6.58 9.59 2.1 2.1 8.06 8.13 9.40 2.8 2.7 9.39 9.47 10.95 3.4 2.7 10.52 10.62 12.27

1.4 2.1 5.15 6.93 8.0 2.1 2.7 6.25 8.41 9.70 2.8 2.7 7.15 9.63 11.13 3.4 2.7 8.06 10.85 12.52

1.4 2.7 3.29 6.65 7.67 2.1 2.7 4.05 8.18 9.45 2.8 2.7 4.66 9.40 10.85 3.4 2.7 5.22 10.54 12.17

1.4 2.7 2.0 8.10 9.35 2.1 3 2.42 9.78 11.30 2.8 3 2.73 11.00 12.70 3.4 3 2.95 11.91 13.77

Fig. 6. Water distribution histogram obtained under different operating pressures (Gungor

**Precip. (cm/h)** 

**Precip. ∆ (cm/h)** 

**Radius (m)** 

**Nozzle Model** 

360°

270°

180°

90°

et. al. 2010).

**Pressure (Psi)** 

Table 1. Technical schedule related to pop up head

Since sprinkler heads make irrigation by throw water towards to air at a certain angle they are highly affected from windy air conditions. By aiming at obtaining the best distribution in windy conditions by irrigation system a number of arrangements in choosing of sprinkler are required (Barrett et. al. 2003). These arrangements may help to perform a better distribution since water which is sprinkled from less wetting scale heads drop closer area and their interaction with contact of wind is less in areas which are exposed to wind excessively. Having the smallest throw angle should be used. Optimal throw angle is 32º for sprinkler irrigation under normal circumstances. However it is required to reduce this angle in windy conditions. Adjusting throw angle as 22-27o in areas where wind speed is higher than 2.6 m/sec shall give better results. However heads are required to be placed in a closer area for corresponding water distribution since fire distance is decreased in this case. Also laterals should be placed vertical to wind direction.

Water distribution uniformity is a parameter that questions situation of hydration of irrigated area with corresponding amount of water. This parameter is one of the main factors which is useful for decreasing system costs thanks to consume of less electric, water, fertilizer and pesticide in connection with its irrigation performance. Different parameters are used by purpose of determining uniformity of water distribution. Parameters which are commonly used are sprinkler uniformity Christiansen's coefficient of uniformity (CU), Distribution Uniformity (DU) and Scheduling coefficient (SC).

#### **4.1.6.1 Distribution uniformity (DU)**

Distribution uniformity is one of the methods which is preferred in determining uniformity in irrigated area. In this method, amount of precipitation is measured by means of caps placed in irrigated area. Then uniformity value is determined by estimating average catch amount belong to quarter which has least water with average catch amount of irrigated area (ASCE.1978). For example, 5 caps Where has the lowest catch amount represent average catch in the low quartile in a test where there are 20 measurement caps (Walker and Skogerboe 1987). Distribution uniformity (DU) should be greater than 75% and if greater than 85% is excellent and acceptable for any sprinkler irrigation. The value of Distribution Uniformity coefficient is calculated using the following expression.

$$\text{DU} \!= (\text{MQM} / \text{M})^{\*} 100\tag{7}$$

Where.

DU: Distribution uniformity, %

MQl: Average collected volume of lower quarter of catch cans, l

M: Average collected volume of all catch cans, l

Distribution uniformity should be at least 70% in rotor heads and 50% in spray heads. As being different from DU, CU and SC parameters can be determined.

#### **4.1.7 Christiansen coefficient of uniformity**

Christiansen Coefficient of Uniformity is used commonly in irrigation sector. Christiansen (1941) developed a formula which depends on average value of irrigation water amount and standard deviation value which are measured through caps placed in irrigated area. CU is calculated by means of formula below.

Irrigation 313

Steps of sprinkler irrigation project are carried out a number of calculations starting from

Sprinkler heads changes according to properties of cross-sectional area of orifice, operating pressure and processing property of orifice. Because of head losses, sprinkler head loses pressure as goes from beginning of lateral towards to end of lateral. Therefore decrease in flows occurs (Anonymous, 2010). Difference of maximum 10% in flow and 20% in pressure across lateral line should be allowed to provide a suitable corresponding water distribution.

q=3600CA√(2gh) (10)

It is defined as water amount given per unit time in irrigation area (Connelan. 2002). It is generally expressed as mm/h. Main factors which affect precipitation rate are sprinkler flow, distance between sprinkler and distance between laterals. The average precipitation

Pr=1000\*q/S\*L (11)

The flow rate of sprinkler heads automatically changes in case of their making irrigation in different angles. For example, when sprinkler angle decrease from 360° to 180° degree, flow rate increases doubled. Therefore in the system where heads having different angle values are used, the average precipitation rate is calculated by means of the following formula.

Pr=360000\*q/ɸS\*L (12)

**5. Planning stages of sprinkler irrigation systems** 

Sprinkler flow is calculated by help of formula below

choice of head and to flow of pump.

Where.Q:Sprinkler flow m3/h C:effective coefficient (0.80-0.95) A: nozzle cross-section area m2 g:gravitational acceleration m/s2

**5.2 Precipitation rate** 

Where.

Where.

h:operation pressure of sprinkler head. m.

rate is calculated with the following equation.

q:the total flow applied to the area by the sprinklers. m3/h S:the spacing between the sprinkler along lateral. m L: The spacing between rows of sprinkler. m

Pr: Average precipitation rate of sprinkler. mm/h 360000:a constant related sprinkler's angel.

q: flow rate of sprinkler. m3/h ɸ: Working angel of sprinkler. 0

Pr:The average precipitation rate. mm/h 1000: a constant which converts meters to mm.

**5.1 Sprinkler flow** 

$$\text{CU} = 100(\text{(1-(7\text{ q})/q})\text{d})\tag{8}$$

Where.

CU: Christiansen coefficient of Uniformity, in % ∆ q͞ : th average absolute deviation from the mean, m3/h q͞ : mean application rate, m3/h

While evaluating CU parameters values which are over or under average are considered as similar. This coefficient is developed for agricultural areas and is not highly useful for turf area. Total variation is applied to define applications which are not uniform. However visual quality should be spread over all area in turf area (IA. 2003). CU values being higher than 84% are suggested as acceptable (Anonymous. 2009).

#### **4.1.8 Scheduling coefficient**

Scheduling coefficient helps us to define how much critical dry area shall be left in irrigated area and irrigation duration being necessary for its application to eliminate this area (Zoldoske. 2003). In calculation of SC. it is useful to be benefitted from computer program. Due to limitations in DU approach SC gains value especially in turf and golf industry (Wilson and Zoldoske, 1997). The driest area is usually user defined as 1. 2. or 5 percent of the coverage area. SC generally varies between 1.1 and 1.4. An efficient irrigation system should aim to achieve a scheduling coefficient less than 1.3.

SC = Average catch overall / Average catch in the critical dry area (9)

#### **4.2 Supplemental irrigation methods in landscape irrigation**

Drip and micro sprinkler irrigation are used in areas here sprinkler irrigation is not appropriate in landscape irrigation. Drip irrigation system is installed in two different types such as under soil and over soil. Water is transmitted to root region through a pipe network and applied here by a means of drippers. Vaporization, runoff and deep seepage into deeper are prevented due to water`s implication by low flow rate in drip irrigation system. Therefore it is irrigation method of which application performance is the highest (Schwankl & Prichard. 1999). Also, drip irrigation minimizes sickness and insect damages because it makes irrigation without wetting leaves. It has less operating pressure. It applies water at fewer amounts as compared to sprinkler irrigation. Problem of weed occurs less because certain part of area is wetted. Also, drip irrigation performs at high efficiency without runoff on hilly terrain. This method is used in soils where area to be irrigated is narrow and saltiness ratio is problematic and resource for water is limited and soil is highly inclined in landscape irrigation (Dines & Brown. 2001).

Micro Sprinkler can be carried out by placing them singularly under trees in situation that drip irrigation can`t provide adequate wetting area. Throw distance of these heads is highly low. However, flow rates changes between 30-300 l/h. accordingly wetting ratio which is requested is provided in a more economic way. Micro sprinkler is developed by the purpose of linking good sides of sprinkler and drip irrigation system.

CU=100((1-(∆ q͞ )/q͞ ) (8)

While evaluating CU parameters values which are over or under average are considered as similar. This coefficient is developed for agricultural areas and is not highly useful for turf area. Total variation is applied to define applications which are not uniform. However visual quality should be spread over all area in turf area (IA. 2003). CU values being higher

Scheduling coefficient helps us to define how much critical dry area shall be left in irrigated area and irrigation duration being necessary for its application to eliminate this area (Zoldoske. 2003). In calculation of SC. it is useful to be benefitted from computer program. Due to limitations in DU approach SC gains value especially in turf and golf industry (Wilson and Zoldoske, 1997). The driest area is usually user defined as 1. 2. or 5 percent of the coverage area. SC generally varies between 1.1 and 1.4. An efficient irrigation system

SC = Average catch overall / Average catch in the critical dry area (9)

Drip and micro sprinkler irrigation are used in areas here sprinkler irrigation is not appropriate in landscape irrigation. Drip irrigation system is installed in two different types such as under soil and over soil. Water is transmitted to root region through a pipe network and applied here by a means of drippers. Vaporization, runoff and deep seepage into deeper are prevented due to water`s implication by low flow rate in drip irrigation system. Therefore it is irrigation method of which application performance is the highest (Schwankl & Prichard. 1999). Also, drip irrigation minimizes sickness and insect damages because it makes irrigation without wetting leaves. It has less operating pressure. It applies water at fewer amounts as compared to sprinkler irrigation. Problem of weed occurs less because certain part of area is wetted. Also, drip irrigation performs at high efficiency without runoff on hilly terrain. This method is used in soils where area to be irrigated is narrow and saltiness ratio is problematic and resource for water is limited and soil is highly inclined in

Micro Sprinkler can be carried out by placing them singularly under trees in situation that drip irrigation can`t provide adequate wetting area. Throw distance of these heads is highly low. However, flow rates changes between 30-300 l/h. accordingly wetting ratio which is requested is provided in a more economic way. Micro sprinkler is developed by the purpose

Where.

CU: Christiansen coefficient of Uniformity, in %

q͞ : mean application rate, m3/h

**4.1.8 Scheduling coefficient** 

∆ q͞ : th average absolute deviation from the mean, m3/h

than 84% are suggested as acceptable (Anonymous. 2009).

should aim to achieve a scheduling coefficient less than 1.3.

**4.2 Supplemental irrigation methods in landscape irrigation** 

landscape irrigation (Dines & Brown. 2001).

of linking good sides of sprinkler and drip irrigation system.
